Laminated-glass interlayer and laminated glass

ABSTRACT

There is provided an interlayer film for laminated glass with which laminated glass having a gradation pattern with suppressed color irregularity can be prepared. The interlayer film for laminated glass according to the present invention is provided with a dark color part, a gradation part and a transparent part, allows laminated glass prepared with two sheets of clear glass to have a parallel light transmittance in a portion of the dark color part less than or equal to 30%, allows the parallel light transmittance in a portion of the gradation part to be continuously increased from the dark color part side to the transparent part side, allows the laminated glass to have a parallel light transmittance in a portion of the transparent part greater than or equal to 60%, allows each of the dark color part, the gradation part and the transparent part to have a first resin layer and allows each of the dark color part and the gradation part to have a second resin layer or allows each of the dark color part, the gradation part and the transparent part to have a second resin layer and allows each of the gradation part and the transparent part to have a first resin layer, and furthermore, allows the thickness of the second resin layer in the gradation part to be continuously decreased from the dark color part side to the transparent part side.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of patent applicationSer. No. 14/442,558, filed on May 13, 2015, which is a 371 applicationof Application Serial No. PCT/JP2013/080814, filed on Nov. 14, 2013,which is based on Japanese Patent Application No. 2012-250437 filed Nov.14, 2012, the entire contents of which are hereby incorporated byreference.

TECHNICAL FIELD

The present invention relates to an interlayer film for laminated glasspartially having a gradation pattern. Moreover, the present inventionrelates to laminated glass prepared with the interlayer film forlaminated glass.

BACKGROUND ART

Laminated glass in which an interlayer film for laminated glass issandwiched between a pair of glass plates has been known. This laminatedglass is widely used for automobiles, railway vehicles, aircraft, ships,buildings and the like. In recent years, as laminated glass forconstruction, there has been a demand for laminated glass having aprivacy protection property. For example, although the laminated glasshaving a privacy protection property can transmit light, it isimpossible to visually recognize a person or an object positioned behindthe laminated glass.

As an example of laminated glass having a privacy protection property,the following Patent Document 1 discloses laminated glass prepared Witha multilayer interlayer film having an opaque layer. In this laminatedglass, by adopting the opaque layer precluding a person or an objectpositioned behind the laminated glass from being visually recognized,the privacy protection property is realized.

Related Art Document

Patent Document

Patent Document 1: WO 2006/082800 A1

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

Due to diversification of applications of laminated glass forconstruction, there has been a demand for laminated glass having anappearance design property of a gradation pattern with suppressed colorirregularity in addition to a privacy protection property. Since thecolor of the laminated glass disclosed in Patent Document 1 is uniformover the whole face of the glass, there is a problem that the appearancedesign property is

An object of the present invention is to provide an interlayer film forlaminated glass with which laminated glass having a gradation patternwith suppressed color irregularity as well as having an excellentprivacy protection property can be prepared, and laminated glassprepared with the interlayer film for laminated glass.

Means for Solving the Problems

According to a broad aspect of the present invention, there is providedan interlayer film for laminated glass, being provided with a dark colorpart, a gradation part and a transparent part, the dark color part, thegradation part and the transparent part being arranged side by side inthe direction orthogonal to the thickness direction in this order,allowing laminated glass to have a parallel light transmittance in aportion of the dark color part less than or equal to 30% at the time ofpreparing the laminated glass with two sheets of clear glass inaccordance with JIS R3202 (1996), allowing the parallel lighttransmittance in a portion of the gradation part of the laminated glassto be continuously increased from the dark color part side to thetransparent part side, and allowing the laminated glass to have aparallel light transmittance in a portion of the transparent partgreater than or equal to 60%, including the following firstconfiguration or including the following second configuration.

The first configuration: Each of the dark color part, the gradation partand the transparent part has a first resin layer containing athermoplastic resin and a plasticizer, each of the dark color part andthe gradation part further has a second resin layer being embedded inthe first resin layer so as to allow the first resin layer to besituated on surfaces at both sides in the thickness direction andcontaining a thermoplastic resin, a plasticizer and inorganic particles,and the thickness of the second resin layer in the gradation part iscontinuously decreased from the dark color part side to the transparentpart side so as to allow the parallel light transmittance in a portionof the gradation part of the laminated glass to be continuouslyincreased from the dark color part side to the transparent part side.

The second configuration: Each of the dark color part, the gradationpart and the transparent part has a second resin layer containing athermoplastic resin, a plasticizer and inorganic particles, each of thegradation part and the transparent part further has a first resin layerbeing embedded in the second resin layer so as to allow the second resinlayer to be situated on surfaces at both sides in the thicknessdirection and containing a thermoplastic resin and a plasticizer, andthe total thickness of the second resin layers in the gradation part iscontinuously decreased from the dark color part side to the transparentpart side so as to allow the parallel light transmittance in a portionof the gradation part of the laminated glass to be continuouslyincreased from the dark color part side to the transparent part side.

According to a broad aspect of the present invention, there is providedan interlayer film for laminated glass (a first interlayer film forlaminated glass including the above-mentioned first configuration),being provided with a dark color part, a gradation part and atransparent part, the dark color part, the gradation part and thetransparent part being arranged side by side in the direction orthogonalto the thickness direction in this order, allowing laminated glass tohave a parallel light transmittance in a portion of the dark color partless than or equal to 30% at the time of preparing the laminated glasswith two sheets of clear glass in accordance with JIS R3202 (1996),allowing the parallel light transmittance in a portion of the gradationpart of the laminated glass to be continuously increased from the darkcolor part side to the transparent part side, and allowing the laminatedglass to have a parallel light transmittance in a portion of thetransparent part greater than or equal to 60%, wherein each of the darkcolor part, the gradation part and the transparent part has a firstresin layer containing a thermoplastic resin and a plasticizer, each ofthe dark color part and the gradation part further has a second resinlayer being embedded in the first resin layer so as to allow the firstresin layer to be situated on surfaces at both sides in the thicknessdirection and containing a thermoplastic resin, a plasticizer andinorganic particles, and the thickness of the second resin layer in thegradation part is continuously decreased from the dark color part sideto the transparent part side so as to allow the parallel lighttransmittance in a portion of the gradation part of the laminated glassto be continuously increased from the dark color part side to thetransparent part side.

According to a broad aspect of the present invention, there is providedan interlayer film for laminated glass (a second interlayer film forlaminated glass including the above-mentioned second configuration),being provided with a dark color part, a gradation part and atransparent part, the dark color part, the gradation part and thetransparent part being arranged side by side in the direction orthogonalto the thickness direction in this order, allowing laminated glass tohave a parallel light transmittance in a portion of the dark color partless than or equal to 30% at the time of preparing the laminated glasswith two sheets of clear glass in accordance with JIS R3202 (1996),allowing the parallel light transmittance in a portion of the gradationpart of the laminated glass to be continuously increased from the darkcolor part side to the transparent part side, and allowing the laminatedglass to have a parallel light transmittance in a portion of thetransparent part greater than or equal to 60%, wherein each of the darkcolor part, the gradation part and the transparent part has a secondresin layer containing a thermoplastic resin, a plasticizer andinorganic particles, each of the gradation part and the transparent partfurther has a first resin layer being embedded in the second resin layerso as to allow the second resin layer to be situated on surfaces at bothsides in the thickness direction and containing a thermoplastic resinand a plasticizer, and the total thickness of the second resin layers inthe gradation part is continuously decreased from the dark color partside to the transparent part side so as to allow the parallel lighttransmittance in a portion of the gradation part of the laminated glassto be continuously increased from the dark color part side to thetransparent part side.

In a specific aspect of the interlayer film for laminated glassaccording to the present invention, the complex viscosity at 200° C. ofthe second resin layer is greater than or equal to 0.7 times and lessthan or equal to 2 times the complex viscosity at 200° C. of the firstresin layer.

According to a broad aspect of the present invention, there is providedlaminated glass including a first laminated glass member, a secondlaminated glass member and the interlayer film for laminated glassdescribed above, wherein the interlayer film for laminated glass isarranged between the first laminated glass member and the secondlaminated glass member.

Effect of the Invention

Since the interlayer film for laminated glass according to the presentinvention is provided with a dark color part, a gradation part and atransparent part, allows the dark color part, the gradation part and thetransparent part to be arranged side by side in the direction orthogonalto the thickness direction in this order, allows laminated glass to havea parallel light transmittance in a portion of the dark color part lessthan or equal to 30% at the time of preparing the laminated glass withtwo sheets of clear glass in accordance with JIS R3202 (1996), allowsthe parallel light transmittance in a portion of the gradation part ofthe laminated glass to be continuously increased from the dark colorpart side to the transparent part side, and allows the laminated glassto have a parallel light transmittance in a portion of the transparentpart greater than or equal to 60%, and furthermore, the interlayer filmfor laminated glass according to the present invention includes thefirst configuration described above or the second configurationdescribed above, it is possible to obtain laminated glass having agradation pattern with suppressed color irregularity as well as havingan excellent privacy protection property.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view showing an interlayer film forlaminated glass in accordance with the first embodiment of the presentinvention.

FIG. 2 is a cross-sectional view showing an interlayer film forlaminated glass in accordance with the second embodiment of the presentinvention.

FIG. 3 is a cross-sectional view showing an interlayer film forlaminated glass in accordance with the third embodiment of the presentinvention.

FIG. 4 is a cross-sectional view showing an interlayer film forlaminated glass in accordance with the fourth embodiment of the presentinvention.

FIG. 5 is a cross-sectional view showing an interlayer film forlaminated glass in accordance with the fifth embodiment of the presentinvention.

FIG. 6 is a cross-sectional view showing an interlayer film forlaminated glass in accordance with the sixth embodiment of the presentinvention.

FIG. 7 is a cross-sectional view showing an interlayer film forlaminated glass in accordance with the seventh embodiment of the presentinvention.

FIG. 8 is a cross-sectional view showing an interlayer film forlaminated glass in accordance with the eighth embodiment of the presentinvention.

FIG. 9 is a cross-sectional view for illustrating another example of theboundary between the gradation part and the transparent part.

FIG. 10 is a cross-sectional view for illustrating another example ofthe boundary between the dark color part and the gradation part.

FIG. 11 is a cross-sectional view showing an example of laminated glassprepared with the interlayer film for laminated glass shown in FIG. 1.

MODE(S) FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail.

The interlayer film for laminated glass according to the presentinvention includes the following main configuration.

Main configuration: The interlayer film for laminated glass is providedwith a dark color part, a gradation part and a transparent part, allowsthe dark color part, the gradation part and the transparent part to bearranged side by side in the direction orthogonal to the thicknessdirection in this order, allows laminated glass to have a parallel lighttransmittance in a portion of the dark color part less than or equal to30% at the time of preparing the laminated glass with two sheets ofclear glass in accordance with JIS R3202 (1996), allows the parallellight transmittance in a portion of the gradation part of the laminatedglass to be continuously increased from the dark color part side to thetransparent part side, and allows the laminated glass to have a parallellight transmittance in a portion of the transparent part greater than orequal to 60%.

In addition to the foregoing main configuration, the interlayer film forlaminated glass according to the present invention includes thefollowing first configuration or the following second configuration.

The first configuration: Each of the dark color part, the gradation partand the transparent part has a first resin layer containing athermoplastic resin and a plasticizer, each of the dark color part andthe gradation part further has a second resin layer being embedded inthe first resin layer so as to allow the first resin layer to besituated on surfaces at both sides in the thickness direction andcontaining a thermoplastic resin, a plasticizer and inorganic particles,and the thickness of the second resin layer in the gradation part iscontinuously decreased from the dark color part side to the transparentpart side so as to allow the parallel light transmittance in a portionof the gradation part of the laminated glass to be continuouslyincreased from the dark color part side to the transparent part side.

The second configuration: Each of the dark color part, the gradationpart and the transparent part has a second resin layer containing athermoplastic resin, a plasticizer and inorganic particles, each of thegradation part and the transparent part further has a first resin layerbeing embedded in the second resin layer so as to allow the second resinlayer to be situated on surfaces at both sides in the thicknessdirection and containing a thermoplastic resin and a plasticizer, andthe total thickness of the second resin layers in the gradation part iscontinuously decreased from the dark color part side to the transparentpart side so as to allow the parallel light transmittance in a portionof the gradation part of the laminated glass to be continuouslyincreased from the dark color part side to the transparent part side.

The interlayer film for laminated glass according to the presentinvention is a first interlayer film for laminated glass including themain configuration and the first configuration or a second interlayerfilm for laminated glass including the main configuration and the secondconfiguration. The interlayer film for laminated glass according to thepresent invention may be the first interlayer film for laminated glassand may be the second interlayer film for laminated glass. It ispreferred that the interlayer film for laminated glass according to thepresent invention be the first interlayer film for laminated glass.

In the first interlayer film for laminated glass, the second resin layeris embedded in the first resin layer so as to allow the first resinlayer to be situated on surfaces at both sides in the thicknessdirection. In the second interlayer film for laminated glass, the firstresin layer is embedded in the second resin layer so as to allow thesecond resin layer to be situated on surfaces at both sides in thethickness direction. The “surfaces at both sides” mean surfaces in alaminate of the first resin layer and the second resin layer. The“surfaces at both sides” may not be outermost surfaces of the interlayerfilm.

Hereinafter, the present invention will be elucidated by describingspecific embodiments of the present invention with reference to thedrawings.

FIG. 1 shows an interlayer film for laminated glass in accordance withthe first embodiment of the present invention represented as across-sectional view.

The interlayer film 1 shown in FIG. 1 is used for obtaining laminatedglass. The interlayer film 1 is an interlayer film for laminated glass.The interlayer film 1 is provided with a dark color part 11, a gradationpart 12 and a transparent part 13. In the interlayer film 1, the darkcolor part 11, the gradation part 12 and the transparent part 13 arearranged side by side in the direction orthogonal to the thicknessdirection of the interlayer film 1 in this order. The interlayer film 1,and an interlayer film 1A, an interlayer film 1B, an interlayer film 10,an interlayer film 1D, an interlayer film 1E and an interlayer film 51which are described below are the first interlayer films for laminatedglass including the main configuration and the first configuration.

The interlayer film 1 and two sheets of clear glass in accordance withJIS R3202 (1996) are used to prepare laminated glass (hereinafter,sometimes described as laminated glass C). Specifically, the interlayerfilm 1 is sandwiched between the two sheets of clear glass to obtain thelaminated glass C. In this case, the parallel light transmittance in aportion of the dark color part 11 of the laminated glass C is less thanor equal to 30%, the parallel light transmittance in a portion of thegradation part 12 of the laminated glass C is continuously increasedfrom the dark color part 11 side to the transparent part 13 side, andthe parallel light transmittance in a portion of the transparent part 13of the laminated glass C is greater than or equal to 60%. In theinterlayer film 1, a broken line X1 is the boundary line which showswhether or not the parallel light transmittance is less than or equal to30%. In the interlayer film 1, a broken line X2 is the boundary linewhich shows whether or not the parallel light transmittance is greaterthan or equal to 60%.

The interlayer film 1 has a first resin layer 16 and a second resinlayer 17. Each of the dark color part 11, the gradation part 12 and thetransparent part 13 has the first resin layer 16. The first resin layer16 contains a thermoplastic resin and a plasticizer. Each of the darkcolor part 11 and the gradation part 12 further has the second resinlayer 17. The second resin layer 17 is embedded in the first resin layer16 so as to allow the first resin layer 16 to be situated on surfaces atboth sides in the thickness direction of the interlayer film 1. Thesecond resin layer 17 contains a thermoplastic resin, a plasticizer andinorganic particles. The second resin layer 17 is lower in transparencythan the first resin layer 16.

In the interlayer film 1, the thickness of the second resin layer 17 inthe gradation part 12 is continuously decreased from the dark color part11 side to the transparent part 13 side so that the parallel lighttransmittance in a portion of the gradation part 12 of the laminatedglass C is continuously increased from the dark color part 11 side tothe transparent part 13 side. Moreover, in the interlayer film 1, thetotal thickness of the first resin layers 16 in the gradation part 12 iscontinuously increased from the dark color part 11 side to thetransparent part 13 side so that the parallel light transmittance in aportion of the gradation part 12 of the laminated glass C iscontinuously increased from the dark color part 11 side to thetransparent part 13 side.

In this connection, as shown in FIG. 9, in an interlayer film 51 havinga dark color part 61 of the same shape as the dark color part 11, havinga gradation part 62 of the same shape as the gradation part 12, having atransparent part 63 of the same shape as the transparent part 13, and asa result thereof, having the same shape as the interlayer film 1, abroken line X2 indicating the boundary line which shows whether or notthe parallel light transmittance is greater than or equal to 60% may bepositioned on the way along which the total thickness of first resinlayers 66 is continuously increased from the dark color part 61 side tothe transparent part 63 side. The boundary between the gradation part 62and the transparent part 63 is determined by whether the parallel lighttransmittance is greater than or equal to 60% or not.

FIG. 2 shows an interlayer film for laminated glass in accordance withthe second embodiment of the present invention represented as across-sectional view.

The interlayer film 1A shown in FIG. 2 is provided with a dark colorpart 11A, a gradation part 12A and a transparent part 13A. In theinterlayer film 1A, the dark color part 11A, the gradation part 12A andthe transparent part 13A are arranged side by side in the directionorthogonal to the thickness direction of the interlayer film 1A in thisorder.

The interlayer film 1A and two sheets of clear glass in accordance withJIS R3202 (1996) are used to prepare laminated glass (hereinafter,sometimes described as laminated glass CA). Specifically, the interlayerfilm 1A is sandwiched between the two sheets of clear glass to obtainthe laminated glass CA. In this case, the parallel light transmittancein a portion of the dark color part 11A of the laminated glass CA isless than or equal to 30%, the parallel light transmittance in a portionof the gradation part 12A of the laminated glass CA is continuouslyincreased from the dark color part 11A side to the transparent part 13Aside, and the parallel light transmittance in a portion of thetransparent part 13A of the laminated glass CA is greater than or equalto 60%. In the interlayer film 1A, a broken line X1 is the boundary linewhich shows whether or not the parallel light transmittance is less thanor equal to 30%. In the interlayer film 1A, a broken line X2 is theboundary line which shows whether or not the parallel lighttransmittance is greater than or equal to 60%.

The interlayer film 1A has a first resin layer 16A and a second resinlayer 17A. Each of the dark color part 11A, the gradation part 12A andthe transparent part 13A has the first resin layer 16A. The first resinlayer 16A contains a thermoplastic resin and a plasticizer. Each of thedark color part 11A and the gradation part 12A further has the secondresin layer 17A. The second resin layer 17A is embedded in the firstresin layer 16A so as to allow the first resin layer 16A to be situatedon surfaces at both sides in the thickness direction of the interlayerfilm 1A. The second resin layer 17A contains a thermoplastic resin, aplasticizer and inorganic particles. The second resin layer 17A is lowerin transparency than the first resin layer 16A.

In the interlayer film 1A, the thickness of the second resin layer 17Ain the gradation part 12A is continuously decreased from the dark colorpart 11A side to the transparent part 13A side so that the parallellight transmittance in a portion of the gradation part 12A of thelaminated glass CA is continuously increased from the dark color part11A side to the transparent part 13A side. Moreover, in the interlayerfilm 1A, the total thickness of the first resin layers 16A in thegradation part 12A is continuously increased from the dark color part11A side to the transparent part 13A side so that the parallel lighttransmittance in a portion of the gradation part 12A of the laminatedglass CA is continuously increased from the dark color part 11A side tothe transparent part 13A side. Moreover, in the interlayer film 1A, thethickness of the second resin layer 17A in the dark color part 11A isdecreased from the outer end part side of the dark color part 11A to thetransparent part 13A side. As described above, the interlayer film 1A inwhich the second resin layer 17A in the dark color part 11A varies inthickness from the outer end part side of the dark color part 11A to thetransparent part 13 side is also one embodiment of the presentinvention.

In this connection, as shown in FIG. 2, in the case where the thicknessof the second resin layer 17A in each of the dark color part 11A and thegradation part 12A is continuously decreased from the outer end partside of the dark color part 11A or the dark color part 11A side to thetransparent part 13A side, an area where the parallel lighttransmittance in the laminated glass CA is less than or equal to 30% isdefined as the dark color part 11A, and an area where the parallel lighttransmittance in the laminated glass CA is greater than 30% is definedas the gradation part 12A.

FIG. 3 shows an interlayer film for laminated glass in accordance withthe third embodiment of the present invention represented as across-sectional view.

The interlayer film 1B shown in FIG. 3 is provided with a dark colorpart 11B, a gradation part 12B and a transparent part 13B. In theinterlayer film 1B, the dark color part 11B, the gradation part 12B andthe transparent part 13B are arranged side by side in the directionorthogonal to the thickness direction of the interlayer film 1B in thisorder.

The interlayer film 1B and two sheets of clear glass in accordance withJIS R3202 (1996) are used to prepare laminated glass (hereinafter,sometimes described as laminated glass CB). Specifically, the interlayerfilm 1B is sandwiched between the two sheets of clear glass to obtainthe laminated glass CB. In this case, the parallel light transmittancein a portion of the dark color part 11B of the laminated glass CB isless than or equal to 30%, the parallel light transmittance in a portionof the gradation part 12B of the laminated glass CB is continuouslyincreased from the dark color part 11B side to the transparent part 13Bside, and the parallel light transmittance in a portion of thetransparent part 13B of the laminated glass CB is greater than or equalto 60%. In the interlayer film 1B, a broken line X1 is the boundary linewhich shows whether or not the parallel light transmittance is less thanor equal to 30%. In the interlayer film 1B, a broken line X2 is theboundary line which shows whether or not the parallel lighttransmittance is greater than or equal to 60%.

The interlayer film 1B has a first resin layer 16B and a second resinlayer 17B. Each of the dark color part 11B, the gradation part 12B andthe transparent part 13B has the first resin layer 16B. The first resinlayer 16B contains a thermoplastic resin and a plasticizer. Each of thedark color part 11B, the gradation part 12B and the transparent part 13Bfurther has the second resin layer 17B. The second resin layer 17B isembedded in the first resin layer 16B so as to allow the first resinlayer 16B to be situated on surfaces at both sides in the thicknessdirection of the interlayer film 1B. The second resin layer 17B containsa thermoplastic resin, a plasticizer and inorganic particles. The secondresin layer 17B is lower in transparency than the first resin layer 16B.

In the interlayer film 1B, the thickness of the second resin layer 17Bin the gradation part 12B is continuously decreased from the dark colorpart 11B side to the transparent part 13B side so that the parallellight transmittance in a portion of the gradation part 12B of thelaminated glass CB is continuously increased from the dark color part11B side to the transparent part 13B side. Moreover, in the interlayerfilm 1B, the total thickness of the first resin layers 16B in thegradation part 12B is continuously increased from the dark color part11B side to the transparent part 13B side so that the parallel lighttransmittance in a portion of the gradation part 12B of the laminatedglass CB is continuously increased from the dark color part 11B side tothe transparent part 13B side. Moreover, in the interlayer film 1B, thethickness of the second resin layer 17B in the dark color part 11B isdecreased from the outer end part side of the dark color part 11B to thetransparent part 13B side. Furthermore, in the interlayer film 1B, thethickness of the second resin layer 17 in the transparent part 13B isdecreased from the dark color part 11B side to the outer end part sideof the transparent part 13B. As described above, the interlayer film 1Bin which the second resin layer 17B in the dark color part 11B and thetransparent part 13B varies in thickness from the outer end part side ofthe dark color part 11B or the dark color part 11B side to thetransparent part 13B side or the outer end part side of the transparentpart 13B is also one embodiment of the present invention.

In this connection, as shown in FIG. 3, in the case where the thicknessof the second resin layer 17B in each of the dark color part 11B, thegradation part 12B and the transparent part 13B is continuouslydecreased from the outer end part side of the dark color part 11B or thedark color part 11B side to the transparent part 13B side or the outerend part side of the transparent part 13B, an area where the parallellight transmittance in the laminated glass CB is less than or equal to30% is defined as the dark color part 11B, an area where the parallellight transmittance in the laminated glass CB is greater than 30% andless than 60% is defined as the gradation part 12B, and an area wherethe parallel light transmittance in the laminated glass CB is greaterthan or equal to 60% is defined as the transparent part 13B.

FIG. 4 shows an interlayer film for laminated glass in accordance withthe fourth embodiment of the present invention represented as across-sectional view.

The interlayer film 10 shown in FIG. 4 is provided with a dark colorpart 11Ca and a dark color part 11Cb, a gradation part 12Ca and agradation part 12Cb, and a transparent part 13C. In the interlayer film10, the dark color part 11Ca, the gradation part 12Ca and thetransparent part 13C are arranged side by side in the directionorthogonal to the thickness direction of the interlayer film 10 in thisorder. Furthermore, in the interlayer film 1C, the dark color part 11Cb,the gradation part 12Cb and the transparent part 13C are arranged sideby side in the direction orthogonal to the thickness direction of theinterlayer film 10 in this order. As described above, the interlayerfilm 10 in which, from each of both ends of the interlayer film 10, thedark color part 1Ca, the gradation part 12Ca and the transparent part13C are arranged side by side in the direction orthogonal to thethickness direction of the interlayer film 10 and the dark color part11Cb, the gradation part 12Cb and the transparent part 13C are arrangedside by side in the direction orthogonal to the thickness direction ofthe interlayer film 10 is also one embodiment of the present invention.

The interlayer film 10 and two sheets of clear glass in accordance withJIS R3202 (1996) are used to prepare laminated glass (hereinafter,sometimes described as laminated glass CC). Specifically, the interlayerfilm 10 is sandwiched between the two sheets of clear glass to obtainthe laminated glass CC. In this case, the parallel light transmittancein each of a portion of the dark color part 11Ca and a portion of thedark color part 11Cb of the laminated glass CC is less than or equal to30%, the parallel light transmittance in each of a portion of thegradation part 12Ca and a portion of the gradation part 12Cb of thelaminated glass CC is continuously increased from the dark color part11Ca or dark color part 11Cb side to the transparent part 13C side, andthe parallel light transmittance in a portion of the transparent part13C of the laminated glass CC is greater than or equal to 60%. In theinterlayer film 1C, each of two broken lines X1 is the boundary linewhich shows whether or not the parallel light transmittance is less thanor equal to 30%. In the interlayer film 10, each of two broken lines X2is the boundary line which shows whether or not the parallel lighttransmittance is greater than or equal to 60%.

The interlayer film 10 has a first resin layer 16C and second resinlayers 17C. Each of the dark color part 11Ca, the dark color part 11Cb,the gradation part 12Ca, the gradation part 12Cb and the transparentpart 13C has the first resin layer 16C. The first resin layer 16Ccontains a thermoplastic resin and a plasticizer. Each of the dark colorpart 11Ca, the dark color part 11Cb, the gradation part 12Ca and thegradation part 12Cb further has the second resin layer 17C. The secondresin layer 17C is embedded in the first resin layer 16C so as to allowthe first resin layer 16C to be situated on surfaces at both sides inthe thickness direction of the interlayer film 10. The second resinlayer 17C contains a thermoplastic resin, a plasticizer and inorganicparticles. The second resin layer 17C is lower in transparency than thefirst resin layer 16C. The second resin layer 17C at the dark color part11Ca side and the second resin layer 17C at the dark color part 11Cbside may be the same as or different from each other.

In the interlayer film 1C, the thickness of the second resin layer 17Cin each of the gradation part 12Ca and the gradation part 12Cb iscontinuously decreased from the dark color part 11Ca or dark color part11Cb side to the transparent part 13C side so that the parallel lighttransmittance in each of a portion of the gradation part 12Ca and aportion of the gradation part 12Cb of the laminated glass CC iscontinuously increased from the dark color part 11Ca or dark color part11Cb side to the transparent part 13C side. Moreover, in the interlayerfilm 1C, the total thickness of the first resin layers 16C in each ofthe gradation part 12Ca and the gradation part 12Cb is continuouslyincreased from the dark color part 11Ca or dark color part 11Cb side tothe transparent part 13C side so that the parallel light transmittancein each of a portion of the gradation part 12Ca and a portion of thegradation part 12Cb of the laminated glass CC is continuously increasedfrom the dark color part 11Ca or dark color part 11Cb side to thetransparent part 13C side.

FIG. 5 shows an interlayer film for laminated glass in accordance withthe fifth embodiment of the present invention represented as across-sectional view.

The interlayer film 1D shown in FIG. 5 is provided with a dark colorpart 11D, a gradation part 12Da and a gradation part 12Db, a transparentpart 13Da, and a transparent part 13Db. In the interlayer film 1D, thedark color part 11D, the gradation part 12Da and the transparent part13Da are arranged side by side in the direction orthogonal to thethickness direction of the interlayer film 1D in this order.Furthermore, in the interlayer film 1D, the dark color part 11D, thegradation part 12Db and the transparent part 13Db are arranged side byside in the direction orthogonal to the thickness direction of theinterlayer film 1D in this order. As described above, the interlayerfilm 1D in which, from the dark color part 11D of the interlayer film 1Dto each of both ends, the dark color part 11D, the gradation part 12Daand the transparent part 13Da are arranged side by side in the directionorthogonal to the thickness direction of the interlayer film 1D and thedark color part 11D, the gradation part 12Db and the transparent part13Db are arranged side by side in the direction orthogonal to thethickness direction of the interlayer film 1D is also one embodiment ofthe present invention.

The interlayer film 1D and two sheets of clear glass in accordance withJIS R3202 (1996) are used to prepare laminated glass (hereinafter,sometimes described as laminated glass CD). Specifically, the interlayerfilm 1D is sandwiched between the two sheets of clear glass to obtainthe laminated glass CD. In this case, the parallel light transmittancein a portion of the dark color part 11D of the laminated glass CD isless than or equal to 30%, the parallel light transmittance in each of aportion of the gradation part 12Da and a portion of the gradation part12Db of the laminated glass CD is continuously increased from the darkcolor part 11D side to each of both ends of the transparent part 13Daand transparent part 13Db sides, and the parallel light transmittance ineach of a portion of the transparent part 13Da and a portion of thetransparent part 13Db of the laminated glass CD is greater than or equalto 60%. In the interlayer film 1D, each of two broken lines X1 is theboundary line which shows whether or not the parallel lighttransmittance is less than or equal to 30%. In the interlayer film 1D,each of two broken lines X2 is the boundary line which shows whether ornot the parallel light transmittance is greater than or equal to 60%.

The interlayer film 1D has a first resin layer 16D and a second resinlayer 17D. Each of the dark color part 11D, the gradation part 12Da, thegradation part 12Db, the transparent part 13Da and the transparent part13Db has the first resin layer 16D. The first resin layer 16D contains athermoplastic resin and a plasticizer. Each of the dark color part 11D,the gradation part 12Da and the gradation part 12Db further has thesecond resin layer 17D. The second resin layer 17D is embedded in thefirst resin layer 16D so as to allow the first resin layer 16D to besituated on surfaces at both sides in the thickness direction of theinterlayer film 1D. The second resin layer 17D contains a thermoplasticresin, a plasticizer and inorganic particles. The second resin layer 17Dis lower in transparency than the first resin layer 16D.

In the interlayer film 1D, the thickness of the second resin layer 17Din each of the gradation part 12Da and the gradation part 12Db iscontinuously decreased from the dark color part 11D side to thetransparent part 13Da or transparent part 13Db side so that the parallellight transmittance in each of a portion of the gradation part 12Da anda portion of the gradation part 12Db of the laminated glass CD iscontinuously increased from the dark color part 11D side to thetransparent part 13Da or transparent part 13Db side. Moreover, in theinterlayer film 1D, the total thickness of the first resin layers 16D ineach of the gradation part 12Da and the gradation part 12Db iscontinuously increased from the dark color part 11D side to thetransparent part 13Da or transparent part 13Db side so that the parallellight transmittance in each of a portion of the gradation part 12Da anda portion of the gradation part 12Db of the laminated glass CD iscontinuously increased from the dark color part 11D side to thetransparent part 13Da or transparent part 13Db side.

FIG. 6 shows an interlayer film for laminated glass in accordance withthe sixth embodiment of the present invention represented as across-sectional view.

The interlayer film 1E shown in FIG. 6 is prepared by allowing theinterlayer film 1 shown in FIG. 1 and a third resin layer 18 to belayered in the thickness direction. As described above, the interlayerfilm 1E containing another resin layer other than the first resin layerand the second resin layer is also one embodiment of the presentinvention.

The interlayer film 1E and two sheets of clear glass in accordance withJIS R3202 (1996) are used to prepare laminated glass (hereinafter,sometimes described as laminated glass CE). Specifically, the interlayerfilm 1E is sandwiched between the two sheets of clear glass to obtainthe laminated glass CE. In this case, the parallel light transmittancein a portion of a dark color part 11E of the laminated glass CE is lessthan or equal to 30%, the parallel light transmittance in a portion of agradation part 12E of the laminated glass CE is continuously increasedfrom the dark color part 11E side to the transparent part 13E side, andthe parallel light transmittance in a portion of a transparent part 13Eof the laminated glass CE is greater than or equal to 60%. In theinterlayer film 1E, a broken line X1 is the boundary line which showswhether or not the parallel light transmittance is less than or equal to30%. In the interlayer film 1E, a broken line X2 is the boundary linewhich shows whether or not the parallel light transmittance is greaterthan or equal to 60%.

The interlayer film 1E has a first resin layer 16, a second resin layer17, and a third resin layer 18. Each of the dark color part 11E, thegradation part 12E and the transparent part 13E has the first resinlayer 16 and the third resin layer 18. The first resin layer 16 containsa thermoplastic resin and a plasticizer. It is preferred that the thirdresin layer 18 contain a thermoplastic resin and a plasticizer. Each ofthe dark color part 11E and the gradation part 12E further has thesecond resin layer 17. The second resin layer 17 is embedded in thefirst resin layer 16 so as to allow the first resin layer 16 to besituated on surfaces at both sides in the thickness direction of alaminate composed of the first resin layer 16X and the second resinlayer 17X (the thickness direction of the interlayer film 1 excludingthe third resin layer 18). The second resin layer 17 contains athermoplastic resin, a plasticizer and inorganic particles. The secondresin layer 17 is lower in transparency than the first resin layer 16.

In the interlayer film 1E, the thickness of the second resin layer 17 inthe gradation part 12E is continuously decreased from the dark colorpart 11E side to the transparent part 13E side so that the parallellight transmittance in a portion of the gradation part 12E of thelaminated glass CE is continuously increased from the dark color part11E side to the transparent part 13E side. Moreover, in the interlayerfilm 1E, the total thickness of the first resin layers 16 in thegradation part 12E is continuously increased from the dark color part11E side to the transparent part 13E side so that the parallel lighttransmittance in a portion of the gradation part 12E of the laminatedglass CE is continuously increased from the dark color part 11E side tothe transparent part 13E side. In this connection, the thickness of thethird resin layer 18 is almost constant over the whole area of theinterlayer film 1E. The thickness of the third resin layer may vary inthe direction orthogonal to the thickness direction of the interlayerfilm.

Moreover, the third resin layers may be arranged on both faces of theinterlayer film 1. Moreover, the second interlayer film for laminatedglass including the above-mentioned second configuration may be providedwith the third resin layer. Moreover, in the interlayer film 1E, anotherresin layer other than the first resin layer 16, the second resin layer17 and the third resin layer 18 may be further layered.

FIG. 7 shows an interlayer film for laminated glass in accordance withthe seventh embodiment of the present invention represented as across-sectional view.

The interlayer film 1X shown in FIG. 7 is used for obtaining laminatedglass. The interlayer film 1X is an interlayer film for laminated glass.The interlayer film 1X is provided with a dark color part 11X, agradation part 12X and a transparent part 13X. In the interlayer film1X, the dark color part 11X, the gradation part 12X and the transparentpart 13X are arranged side by side in the direction orthogonal to thethickness direction of the interlayer film 1X in this order. Theinterlayer film 1X, and an interlayer film 1Y and an interlayer film 51Xwhich are described below are the second interlayer films for laminatedglass including the main configuration and the second configuration.

The interlayer film 1X and two sheets of clear glass in accordance withJIS R3202 (1996) are used to prepare laminated glass (hereinafter,sometimes described as laminated glass CX). Specifically, the interlayerfilm 1X is sandwiched between the two sheets of clear glass to obtainthe laminated glass CX. In this case, the parallel light transmittancein a portion of the dark color part 11X of the laminated glass CX isless than or equal to 30%, the parallel light transmittance in a portionof the gradation part 12X of the laminated glass CX is continuouslyincreased from the dark color part 11X side to the transparent part 13Xside, and the parallel light transmittance in a portion of thetransparent part 13X of the laminated glass CX is greater than or equalto 60%. In the interlayer film 1X, a broken line X1 is the boundary linewhich shows whether or not the parallel light transmittance is less thanor equal to 30%. In the interlayer film 1X, a broken line X2 is theboundary line which shows whether or not the parallel lighttransmittance is greater than or equal to 60%.

The interlayer film 1X has a first resin layer 16X and a second resinlayer 17X. Each of the dark color part 11X, the gradation part 12X andthe transparent part 13X has the second resin layer 17X. The secondresin layer 17X contains a thermoplastic resin, a plasticizer andinorganic particles. Each of the gradation part 12X and the transparentpart 13X further has the first resin layer 16X. The first resin layer16X is embedded in the second resin layer 17X so as to allow the secondresin layer 17X to be situated on surfaces at both sides in thethickness direction of the interlayer film 1X. The first resin layer 16Xcontains a thermoplastic resin and a plasticizer. The second resin layer17X is lower in transparency than the first resin layer 16X.

In the interlayer film 1X, the total thickness of the second resinlayers 17X in the gradation part 12X is continuously decreased from thedark color part 11X side to the transparent part 13X side so that theparallel light transmittance in a portion of the gradation part 12X ofthe laminated glass CX is continuously increased from the dark colorpart 11X side to the transparent part 13X side. Moreover, in theinterlayer film 1X, the thickness of the first resin layer 16X in thegradation part 12X is continuously increased from the dark color part11X side to the transparent part 13X side so that the parallel lighttransmittance in a portion of the gradation part 12X of the laminatedglass CX is continuously increased from the dark color part 11X side tothe transparent part 13X side. The interlayer film 1X thus prepared isalso one embodiment of the present invention.

In this connection, as shown in FIG. 10, in an interlayer film 51Xhaving a dark color part 61X of the same shape as the dark color part11X, having a gradation part 62X of the same shape as the gradation part12X, having a transparent part 63X of the same shape as the transparentpart 13X, and as a result thereof, having the same shape as theinterlayer film 1X, a broken line X1 indicating the boundary line whichshows whether or not the parallel light transmittance is less than orequal to 30% may be positioned on the way along which the totalthickness of second resin layers 67X is continuously decreased from thedark color part 61X side to the transparent part 63X side. The boundarybetween the dark color part 61X and the gradation part 62X is determinedby whether the parallel light transmittance is less than or equal to 30%or not.

FIG. 8 shows an interlayer film for laminated glass in accordance withthe eighth embodiment of the present invention represented as across-sectional view.

The interlayer film 1Y shown in FIG. 8 is provided with a dark colorpart 11Y, a gradation part 12Y and a transparent part 13Y. In theinterlayer film 1Y, the dark color part 11Y, the gradation part 12Y andthe transparent part 13Y are arranged side by side in the directionorthogonal to the thickness direction of the interlayer film 1Y in thisorder.

The interlayer film 1Y and two sheets of clear glass in accordance withJIS R3202 (1996) are used to prepare laminated glass (hereinafter,sometimes described as laminated glass CY). Specifically, the interlayerfilm 1Y is sandwiched between the two sheets of clear glass to obtainthe laminated glass CY. In this case, the parallel light transmittancein a portion of the dark color part 11Y of the laminated glass CY isless than or equal to 30%, the parallel light transmittance in a portionof the gradation part 12Y of the laminated glass CY is continuouslyincreased from the dark color part 11Y side to the transparent part 13Yside, and the parallel light transmittance in a portion of thetransparent part 13Y of the laminated glass CY is greater than or equalto 60%. In the interlayer film 1Y, a broken line X1 is the boundary linewhich shows whether or not the parallel light transmittance is less thanor equal to 30%. In the interlayer film 1Y, a broken line X2 is theboundary line which shows whether or not the parallel lighttransmittance is greater than or equal to 60%.

The interlayer film 1Y has a first resin layer 16Y and a second resinlayer 17Y. Each of the dark color part 11Y, the gradation part 12Y andthe transparent part 13Y has the second resin layer 17Y. The secondresin layer 17Y contains a thermoplastic resin, a plasticizer andinorganic particles. Each of the gradation part 12Y and the transparentpart 13Y further has the first resin layer 16Y. The first resin layer16Y is embedded in the second resin layer 17Y so as to allow the secondresin layer 17Y to be situated on surfaces at both sides in thethickness direction of the interlayer film 1Y. The first resin layer 16Ycontains a thermoplastic resin and a plasticizer. The second resin layer17Y is lower in transparency than the first resin layer 16Y.

In the interlayer film 1Y, the total thickness of the second resinlayers 17Y in the gradation part 12Y is continuously decreased from thedark color part 11Y side to the transparent part 13Y side so that theparallel light transmittance in a portion of the gradation part 12Y ofthe laminated glass CY is continuously increased from the dark colorpart 11Y side to the transparent part 13Y side. Moreover, in theinterlayer film 1Y, the thickness of the first resin layer 16Y in thegradation part 12Y is continuously increased from the dark color part11Y side to the transparent part 13Y side so that the parallel lighttransmittance in a portion of the gradation part 12Y of the laminatedglass CY is continuously increased from the dark color part 11Y side tothe transparent part 13Y side. Moreover, in the interlayer film 1Y, thetotal thickness of the second resin layers 17Y in the transparent part13Y is decreased from the dark color part 11Y side to the outer end partside of the transparent part 13Y. As described above, the interlayerfilm 1Y in which the second resin layers 17Y in the dark color part 11Yvary in the total thickness from the dark color part 11Y side to theouter end part side of the transparent part 13Y is also one embodimentof the present invention.

In this connection, as shown in FIG. 8, in the case where the totalthickness of the second resin layers 17Y in each of the transparent part13Y and the gradation part 12Y is continuously decreased from the darkcolor part 11Y side to the outer end part side of the transparent part13Y, an area where the parallel light transmittance in the laminatedglass CY is greater than or equal to 60% is defined as the transparentpart 13Y, and an area where the parallel light transmittance in thelaminated glass CY is less than 60% is defined as the gradation part12Y.

By using such an interlayer film 1, an interlayer film 51, an interlayerfilm 1A, an interlayer film 1B, an interlayer film 1C, an interlayerfilm 1D, an interlayer film 1E, an interlayer film 1X, an interlayerfilm 51X, and an interlayer film 1Y mentioned above, it is possible toobtain laminated glass having a gradation pattern with suppressed colorirregularity as well as having an excellent privacy protection property.In laminated glass prepared with the interlayer film 1, the interlayerfilm 51, the interlayer film 1A, the interlayer film 1B, the interlayerfilm 1C, the interlayer film 1D, the interlayer film 1E, the interlayerfilm 1X, the interlayer film 51X, or the interlayer film 1Y, althoughthe laminated glass transmits light, it is possible to allow thelaminated glass to have an area through which a person or an objectpositioned therebehind cannot be visually recognized.

The maximum value of the parallel light transmittance in a portion ofthe transparent part of laminated glass such as the laminated glass C,the laminated glass CA, the laminated glass CB, the laminated glass CC,the laminated glass CD, the laminated glass CE, the laminated glass CXand the laminated glass CY is preferably greater than or equal to 70%and more preferably greater than or equal to 78%. When the maximum valueof the parallel light transmittance in a portion of the transparent partis greater than or equal to the above lower limit, laminated glassfurther excellent in lighting properties is obtained. The minimum valueof the parallel light transmittance in a portion of the dark color partof the laminated glass is preferably less than or equal to 20%, morepreferably less than or equal to 10%, further preferably less than orequal to 5%, and most preferably less than or equal to 2%. When theminimum value of the parallel light transmittance in a portion of thedark color part is less than or equal to the above upper limit,laminated glass further excellent in the privacy protection property isobtained.

The parallel light transmittance is measured in accordance with JISR3106 (1998). Specifically, the laminated glass in a state of beinginstalled on the light path between a light source and an integratingsphere, in parallel to the normal line of the optical axis and at apoint apart from the integrating sphere by 13 cm so that only thetransmitted parallel light is received by the integrating sphere ismeasured using a spectrophotometer. The parallel light transmittancemeans a visible light transmittance calculated from the spectraltransmittance measured in this state. Examples of the spectrophotometerinclude “U-4100” available from Hitachi High-Technologies Corporation,and the like.

The maximum value of the total light transmittance in a portion of thetransparent part of laminated glass such as the laminated glass C, thelaminated glass CA, the laminated glass CB, the laminated glass CC, thelaminated glass CD, the laminated glass CE, the laminated glass CX andthe laminated glass CY is preferably greater than or equal to 60%, morepreferably greater than or equal to 70%, further preferably greater thanor equal to 80%, and most preferably greater than or equal to 85%. Whenthe maximum value of the total light transmittance in a portion of thetransparent part is greater than or equal to the above lower limit,laminated glass further excellent in lighting properties is obtained.The minimum value of the total light transmittance in a portion of thedark color part of the laminated glass is preferably greater than orequal to 5%, more preferably greater than or equal to 50%, furtherpreferably greater than or equal to 60%, and especially preferablygreater than or equal to 75%. When the minimum value of the total lighttransmittance in a portion of the dark color part is greater than orequal to the above lower limit, laminated glass further excellent inlighting properties is obtained. Moreover, the total light transmittancerefers to the total of the parallel light transmittance and the diffusedlight transmittance.

The total light transmittance is measured in accordance with JIS R3106(1998). Specifically, the obtained laminated glass is installed inparallel to and brought into close contact with an opening part of anintegrating sphere so that all light rays transmitted are received bythe integrating sphere using a spectrophotometer to measure the spectraltransmittance. The total light transmittance means a visible lighttransmittance calculated from the spectral transmittance measured inthis state. Examples of the spectrophotometer include “U-4100” availablefrom Hitachi High-Technologies Corporation, and the like.

In a portion of the dark color part of laminated glass such as thelaminated glass C, the laminated glass CA, the laminated glass CB, thelaminated glass CC, the laminated glass CD, the laminated glass CE, thelaminated glass CX and the laminated glass CY, it is preferred that theminimum value of the total light transmittance be greater than or equalto 75% in the case where the minimum value of the parallel lighttransmittance is greater than 20% and less than or equal to 30%, it ispreferred that the minimum value of the total light transmittance begreater than or equal to 65% in the case where the minimum value of theparallel light transmittance is greater than 5% and less than or equalto 20%, and it is preferred that the minimum value of the total lighttransmittance be greater than or equal to 50% in the case where theminimum value of the parallel light transmittance is less than or equalto 5%. In a portion of the dark color part of laminated glass such asthe laminated glass C, the laminated glass CA, the laminated glass CB,the laminated glass CC, the laminated glass CD, the laminated glass CE,the laminated glass CX and the laminated glass CY, it is preferred thatthe minimum value of the parallel light transmittance be less than orequal to 30% and the minimum value of the total light transmittance begreater than or equal to 75%, it is preferred that the minimum value ofthe parallel light transmittance be less than or equal to 20% and theminimum value of the total light transmittance be greater than or equalto 65%, and it is preferred that the minimum value of the parallel lighttransmittance be less than or equal to 5% and the minimum value of thetotal light transmittance be greater than or equal to 40%. In a portionof the dark color part of laminated glass such as the laminated glass C,the laminated glass CA, the laminated glass CB, the laminated glass CC,the laminated glass CD, the laminated glass CE, the laminated glass CXand the laminated glass CY, it is preferred that the minimum value ofthe total light transmittance be greater than or equal to 45% in thecase where the minimum value of the parallel light transmittance isgreater than or equal to 0.5%. When the minimum value of the parallellight transmittance and the minimum value of the total lighttransmittance in a portion of the dark color part satisfy theabove-described requirement, with regard to the laminated glass, it ispossible to further enhance the privacy protection property whilemaintaining the lighting properties high.

The average value of the thicknesses (T) of the interlayer film (seeFIGS. 1 to 10) is not particularly limited. From the viewpoint of thepractical aspect, the average value of the thicknesses (T) of theinterlayer film is preferably greater than or equal to 0.1 mm, morepreferably greater than or equal to 0.25 mm, preferably less than orequal to 3 mm, and more preferably less than or equal to 1.5 mm. Whenthe average value of the thicknesses (T) of the interlayer film isgreater than or equal to the above lower limit, the penetrationresistance of laminated glass is enhanced.

With regard to the first interlayer film for laminated glass includingthe above-mentioned first configuration, over the whole area of theportion of the dark color part, the portion of the gradation part andthe portion of the transparent part, the maximum value and the minimumvalue of the total thickness (T1+T2) of the first resin layers (seeFIGS. 1 to 6, 9) are not particularly limited. From the viewpoint of thepractical aspect, over the whole area of the portion of the dark colorpart, the portion of the gradation part and the portion of thetransparent part, the minimum value of the total thickness (T1+T2) ofthe first resin layers is preferably greater than or equal to 0.08 mm,more preferably greater than or equal to 0.12 mm, preferably less thanor equal to 3 mm, and more preferably less than or equal to 1.5 mm. Overthe whole area of the portion of the dark color part, the portion of thegradation part and the portion of the transparent part, the maximumvalue of the total thickness (T1+T2) of the first resin layers ispreferably greater than or equal to 0.1 mm, more preferably greater thanor equal to 0.25 mm, preferably less than or equal to 3 mm, and morepreferably less than or equal to 1.5 mm. When each of the minimum valueand the maximum value of the total thickness (T1+T2) of the first resinlayers is greater than or equal to the above lower limit, thepenetration resistance of laminated glass is further enhanced. When eachof the minimum value and the maximum value of the total thickness(T1+T2) of the first resin layers is less than or equal to the aboveupper limit, laminated glass further excellent in lighting properties isobtained. In this connection, in the portion of the dark color part andthe portion of the gradation part, each of the minimum value and themaximum value of the total thickness (T1+T2) of the first resin layersrefers to the total thickness of two first resin layers at both sides.With regard to the interlayer film 1, the interlayer film 1A, theinterlayer film 1C, the interlayer film 1D, the interlayer film 1E andthe interlayer film 51 shown in FIGS. 1, 2, 4, 5, 6 and 9, in theportion of the transparent part, each of the minimum value and themaximum value of the total thickness (T1+T2) of the first resin layersrefers to the thickness of the transparent part itself. In general, theminimum value of the total thickness (T1+T2) of the first resin layersis calculated at the dark color part or calculated at the dark colorpart side end part of the gradation part. In general, the maximum valueof the total thickness (T1+T2) of the first resin layers is calculatedat the transparent part or calculated at the transparent part side endpart of the gradation part.

In this connection, with regard to the two first resin layers situatedon surfaces at both sides of the interlayer film in the portion of thedark color part and the portion of the gradation part, the thickness(T1) of the one first resin layer and the thickness (T2) of the otherfirst resin layer may be the same as or different from each other.

The maximum value of the thickness (T3) of the second resin layer (seeFIGS. 1 to 6, 9) in the whole area of the dark color part and thegradation part is not particularly limited. The maximum value of thethickness (T3) of the second resin layer in the whole area of the darkcolor part and the gradation part is preferably greater than or equal to0.001 mm, preferably less than or equal to 0.8 mm, and more preferablyless than or equal to 0.3 mm. When the maximum value of the thickness ofthe second resin layer is greater than or equal to the above lowerlimit, the parallel light transmittance in a portion of the dark colorpart of the laminated glass is further lowered, and laminated glassfurther excellent in the privacy protection property is obtained. Whenthe maximum value of the thickness of the second resin layer is lessthan or equal to the above upper limit, laminated glass furtherexcellent in lighting properties is obtained. In general, the maximumvalue of the thickness (T3) of the second resin layer is calculated atthe dark color part or calculated at the dark color part side end partof the gradation part.

It is preferred that the total thickness (T1+T2) of the first resinlayers in the dark color part be almost constant. The ratio of themaximum value of the total thickness (T1+T2) of the first resin layersin the dark color part to the minimum value of the total thickness(T1+T2) of the first resin layers in the dark color part is greater thanor equal to 1, preferably less than or equal to 5, and more preferablyless than or equal to 2.

In the case where the interlayer film for laminated glass according tothe present invention contains a third resin layer, the thickness (T7)of the third resin layer (see FIG. 6) is not particularly limited. Thethickness (T7) of the third resin layer is preferably greater than orequal to 0.03 mm, more preferably greater than or equal to 0.05 mm,preferably less than or equal to 0.3 mm, and more preferably less thanor equal to 0.15 mm. When the thickness of the third resin layer isgreater than or equal to the above lower limit, the penetrationresistance and the sound insulating properties of laminated glass isfurther enhanced. When the thickness of the third resin layer is lessthan or equal to the above upper limit, laminated glass furtherexcellent in lighting properties is obtained. In this connection, in thecase where the third resin layers are arranged at both faces of theinterlayer film, the thickness (T7) of the third resin layer refers tothe total thickness of the third resin layers.

With regard to the second interlayer film for laminated glass includingthe above-mentioned second configuration, over the whole area of theportion of the dark color part, the portion of the gradation part andthe portion of the transparent part, the maximum value and the minimumvalue of the total thickness (T4+T5) of the second resin layers (seeFIGS. 7, 8, 10) are not particularly limited. From the viewpoint of thepractical aspect, over the whole area of the portion of the dark colorpart, the portion of the gradation part and the portion of thetransparent part, the minimum value of the total thickness (T4+T5) ofthe second resin layers is preferably greater than or equal to 0.05 mm,more preferably greater than or equal to 0.1 mm, preferably less than orequal to 3 mm, and more preferably less than or equal to 1.5 mm. Overthe whole area of the portion of the dark color part, the portion of thegradation part and the portion of the transparent part, the maximumvalue of the total thickness (T4+T5) of the second resin layers ispreferably greater than or equal to 0.3 mm, more preferably greater thanor equal to 0.45 mm, preferably less than or equal to 3 mm, and morepreferably less than or equal to 1.5 mm. When each of the minimum valueand the maximum value of the total thickness (T4+T5) of the second resinlayers is greater than or equal to the above lower limit, thepenetration resistance of laminated glass is further enhanced. When eachof the minimum value and the maximum value of the total thickness(T4+T5) of the second resin layers is less than or equal to the aboveupper limit, laminated glass further excellent in lighting properties isobtained. In this connection, in the portion of the transparent part andthe portion of the gradation part, each of the minimum value and themaximum value of the total thickness (T4+T5) of the second resin layersrefers to the total thickness of two second resin layers at both sides.With regard to the interlayer films 1X, 1Y and 51X shown in FIGS. 7, 8and 10, in the portion of the dark color part, each of the minimum valueand the maximum value of the total thickness (T4+T5) of the second resinlayers refers to the thickness of the portion itself of the dark colorpart. In general, the maximum value of the total thickness (T4+T5) ofthe second resin layers is calculated at the dark color part orcalculated at the dark color part side end part of the gradation part.In general, the minimum value of the total thickness (T4+T5) of thesecond resin layers is calculated at the transparent part or calculatedat the transparent part side end part of the gradation part.

In this connection, with regard to the two second resin layers situatedon surfaces at both sides of the interlayer film in the portion of thetransparent part and the portion of the gradation part, the thickness(T4) of the one second resin layer and the thickness (T5) of the othersecond resin layer may be the same as or different from each other.

The maximum value of the thickness (T6) of the first resin layer (seeFIGS. 7, 8, 10) in the whole area of the transparent part and thegradation part is not particularly limited. The maximum value of thethickness (T6) of the first resin layer in the whole area of thetransparent part and the gradation part is preferably greater than orequal to 0.2 mm, more preferably greater than or equal to 0.4 mm,preferably less than or equal to 0.75 mm, and more preferably less thanor equal to 0.58 mm. When the maximum value of the thickness of thefirst resin layer is greater than or equal to the above lower limit, theparallel light transmittance in a portion of the transparent part of thelaminated glass is further heightened, and laminated glass furtherexcellent in lighting properties is obtained. When the maximum value ofthe thickness of the first resin layer is less than or equal to theabove upper limit, laminated glass further excellent in the privacyprotection property is obtained. In general, the maximum value of thethickness (T6) of the first resin layer is calculated at the transparentpart or calculated at the transparent part side end part of thegradation part.

It is preferred that the total thickness (T4+T5) of the second resinlayers in the transparent part be almost constant. The ratio of themaximum value of the total thickness (T4+T5) of the second resin layersin the transparent part to the minimum value of the total thickness(T4+T5) of the second resin layers in the transparent part is greaterthan or equal to 1, preferably less than or equal to 5, and morepreferably less than or equal to 2.

It is preferred that the thickness (T6) of the first resin layer in thetransparent part be almost constant. The ratio of the maximum value ofthe thickness (T6) of the first resin layer in the transparent part tothe minimum value of the thickness (T6) of the first resin layer in thetransparent part is greater than or equal to 1, preferably less than orequal to 5, and more preferably less than or equal to 2.

In this connection, the thickness of each of the interlayer film and therespective layers is measured in the following manner.

The interlayer film is cut with a sharp razor blade so that thecross-section (the cross-section shown in each of FIGS. 1 to 10) of thedark color part, the gradation part and the transparent part in thelayered direction including the dark color part, the gradation part andthe transparent part is exposed. Afterward, the exposed cross-section ofthe interlayer film is observed with a digital microscope (“DSX500”available from Olympus Corporation) to measure the thicknesses of theinterlayer film and respective layers with a micro gauge.

The length (L1) of the dark color part (see FIGS. 1 to 10) is preferablygreater than or equal to 25 mm, more preferably greater than or equal to100 mm, further preferably greater than or equal to 200 mm, especiallypreferably greater than or equal to 300 mm, preferably less than orequal to 2000 mm, more preferably less than or equal to 1500 mm, furtherpreferably less than or equal to 1000 mm, especially preferably lessthan or equal to 700 mm, and most preferably less than or equal to 500mm. In this connection, in the case where there are plural dark colorparts, the length (L1) of the dark color part refers to the length perone dark color part.

The length (L2) of the gradation part (see FIGS. 1 to 10) is preferablygreater than or equal to 10 mm, preferably less than or equal to 1500mm, more preferably less than or equal to 1000 mm, further preferablyless than or equal to 500 mm, and most preferably less than or equal to300 mm. In this connection, in the case where there are plural gradationparts, the length (L2) of the gradation part refers to the length perone gradation part.

The length (L3) of the transparent part (see FIGS. 1 to 10) is notparticularly limited and appropriately adjusted depending on theapplication of the interlayer film and the laminated glass, and thelike. In this connection, in the case where there are plural transparentparts, the length (L3) of the transparent part refers to the length perone transparent part.

The lengths (L1, L2, L3) of the dark color part, the gradation part andthe transparent part mean the lengths of the dark color part, thegradation part and the transparent part in the direction along which thedark color part, the gradation part and the transparent part arearranged side by side.

It is preferred that the complex viscosity at 200° C. of the secondresin layer be greater than or equal to 0.7 times the complex viscosityat 200° C. of the first resin layer, it is more preferred that thecomplex viscosity be greater than or equal to 0.8 time, it is furtherpreferred that the complex viscosity be greater than or equal to 0.9time, it is preferred that the complex viscosity be less than or equalto 2 times, it is more preferred that the complex viscosity be less thanor equal to 1.5 times, and it is further preferred that the complexviscosity be less than or equal to 1.3 times. When the complexviscosities of the first resin layer and the second resin layer satisfythe above-mentioned requirement, it is possible to obtain laminatedglass further excellent in the appearance design property in which thecolor irregularity is further suppressed.

Although the measurement method of the complex viscosity is notparticularly limited, for example, the complex viscosity can be measuredby the following method. With regard to the interlayer film forlaminated glass according to the present invention, the first resinlayer and the second resin layer are peeled off from each other and thefirst resin layer is removed. In a molding flask (2 cm in longitudinallength by 2 cm in transversal length by 0.76 mm in thickness) arrangedbetween two sheets of polyethylene terephthalate (PET) films, 1 g of thefirst resin layer peeled off is placed and preheated for 10 minutes at atemperature of 150° C. and under a pressure of 0 kg/cm², and thenpress-molded for 15 minutes under a pressure of 80 kg/cm². Afterward, ina hand press machine previously set to 20° C., the press-molded firstresin layer is installed and pressed for 10 minutes at 10 MPa to becooled. Then, from the molding flask arranged between the two sheets ofPET films, one sheet of the PET film is peeled off, and the press-moldedproduct is stored for 24 hours in a constant-temperature andconstant-humidity chamber (a humidity of 30% (±30), a temperature of 23°C.), and then measured for the viscoelasticity, using the ARES-G2available from TA Instruments Japan Inc., in accordance with JISK7244-10 (ISO6721-10) to measure the complex viscosity. As a jig used atthe time of the viscoelasticity measurement, a parallel plate with adiameter of 8 mm is used. Moreover, the viscoelasticity measurement isperformed under conditions of a frequency of 1 Hz and a strain of 8% atthe measurement temperature of 200° C. The obtained complex viscosity isread as a value of the complex viscosity of the first resin layer at200° C. Moreover, the complex viscosity of the second resin layer ismeasured in the same manner.

By allowing the content of the plasticizer which the first resin layercontains to be increased, it is possible to decrease the complexviscosity of the first resin layer. Moreover, by allowing the content ofthe plasticizer which the second resin layer contains to be increased,it is possible to decrease the complex viscosity of the second resinlayer.

The complex viscosity can be measured by using a sample obtained at theend of 1 hour after the ingredients constituting the interlayer film forlaminated glass according to the present invention are formed into aninterlayer film for laminated glass, a first resin layer or a secondresin layer. The interlayer film for laminated glass according to thepresent invention, or the first resin layer or the second resin layercontained in the interlayer film for laminated glass according to thepresent invention is obtained and then the complex viscosity can bemeasured. It is preferred that the measurement of the complex viscositybe initiated at the end of 1 hour after an interlayer film for laminatedglass, a first resin layer or a second resin layer is obtained by usingthe ingredients constituting the interlayer film for laminated glassaccording to the present invention.

Hereinafter, the details of each ingredient used for the first resinlayer and the second resin layer will be described.

(Thermoplastic Resin)

Each of the first resin layer and the second resin layer contains athermoplastic resin. It is preferred that the third resin layer containa thermoplastic resin. The thermoplastic resin in the first resin layer,the thermoplastic resin in the second resin layer and the thermoplasticresin in the third resin layer are not particularly limited. As thethermoplastic resin, a conventionally known thermoplastic resin can beused. One kind of the thermoplastic resin may be used alone, and two ormore kinds thereof may be combinedly used. The thermoplastic resin inthe first resin layer, the thermoplastic resin in the second resin layerand the thermoplastic resin in the third resin layer may be the same asor different from one another.

Examples of the thermoplastic resin include a polyvinyl acetal resin, anethylene-vinyl acetate copolymer resin, an ethylene-acrylic copolymerresin, a polyurethane resin, a polyvinyl alcohol resin, and the like.Thermoplastic resins other than these may be used.

It is preferred that the thermoplastic resin be a polyvinyl acetalresin. By using a polyvinyl acetal resin and a plasticizer together, theadhesive force of the interlayer film to a laminated glass member isfurther heightened.

For example, the polyvinyl acetal resin can be produced by acetalizingpolyvinyl alcohol with an aldehyde. For example, the polyvinyl alcoholis obtained by saponifying polyvinyl acetate. The saponification degreeof the polyvinyl alcohol generally lies within the range of 80 to 99.8%by mole.

The average polymerization degree of the polyvinyl alcohol is preferablygreater than or equal to 200, more preferably greater than or equal to500, preferably less than or equal to 5000, more preferably less than orequal to 3500, and further preferably less than or equal to 3000. Whenthe average polymerization degree is greater than or equal to the abovelower limit, the penetration resistance of laminated glass is furtherenhanced. When the average polymerization degree is less than or equalto the above upper limit, the resin is easily formed into an interlayerfilm. Moreover, by heightening the average polymerization degree of thepolyvinyl alcohol, the complex viscosity of the resulting polyvinylacetal resin can be increased and the complex viscosity of the firstresin layer or the second resin layer can be increased.

The aldehyde is not particularly limited. In general, as the aldehyde,an aldehyde with 1 to 10 carbon atoms is suitably used. Examples of thealdehyde with 1 to 10 carbon atoms include formaldehyde, acetaldehyde,propionaldehyde, n-butyraldehyde, isobutyraldehyde, n-valeraldehyde,2-ethylbutyraldehyde, n-hexylaldehyde, n-octylaldehyde, n-nonylaldehyde,n-decylaldehyde, benzaldehyde, and the like. Of these, propionaldehyde,n-butyraldehyde, isobutyraldehyde, n-hexylaldehyde or n-valeraldehyde ispreferred, propionaldehyde, n-butyraldehyde or isobutyraldehyde is morepreferred, and n-butyraldehyde is further preferred. It is preferredthat the number of carbon atoms of the aldehyde be 3 or 4, and it ismore preferred that the number of carbon atoms of the aldehyde be 4. Onekind of the aldehyde may be used alone, and two or more kinds thereofmay be combinedly used.

The content ratio of the hydroxyl group (the amount of hydroxyl groups)of the polyvinyl acetal resin is preferably greater than or equal to 10%by mole, more preferably greater than or equal to 15% by mole, furtherpreferably greater than or equal to 18% by mole, preferably less than orequal to 40% by mole, and more preferably less than or equal to 35% bymole. When the content ratio of the hydroxyl group is greater than orequal to the above lower limit, the adhesive force of the interlayerfilm is further heightened. Moreover, when the content ratio of thehydroxyl group is less than or equal to the above upper limit, theflexibility of the interlayer film is enhanced and the handling of theinterlayer film is facilitated. Moreover, by heightening the contentratio of the hydroxyl group of the polyvinyl acetal resin, the complexviscosity of the polyvinyl acetal resin can be increased and the complexviscosity of the first resin layer or the second resin layer can beincreased.

The content ratio of the hydroxyl group of the polyvinyl acetal resin isa value expressing the mole fraction determined by dividing the amountof ethylene groups to which the hydroxyl group is bonded by the totalamount of ethylene groups in the main chain in terms of percentage. Forexample, the amount of ethylene groups to which the hydroxyl group isbonded can be measured in accordance with JIS K6726 “Testing methods forpolyvinyl alcohol” or in accordance with ASTM D1396-92 to be determined.

The acetylation degree (the amount of acetyl groups) of the polyvinylacetal resin is preferably greater than or equal to 0.1% by mole, morepreferably greater than or equal to 0.3% by mole, further preferablygreater than or equal to 0.5% by mole, preferably less than or equal to30% by mole, more preferably less than or equal to 25% by mole, andfurther preferably less than or equal to 20% by mole. When theacetylation degree is greater than or equal to the above lower limit,the compatibility between the polyvinyl acetal resin and a plasticizeris heightened. When the acetylation degree is less than or equal to theabove upper limit, the moisture resistance of the interlayer film andlaminated glass is enhanced.

The acetylation degree is a value expressing the mole fractiondetermined by dividing a value obtained by subtracting the amount ofethylene groups to which the acetal group is bonded and the amount ofethylene groups to which the hydroxyl group is bonded from the totalamount of ethylene groups in the main chain by the total amount ofethylene groups in the main chain in terms of percentage. For example,the amount of ethylene groups to which the acetal group is bonded can bemeasured in accordance with JIS K6728 “Testing methods for polyvinylbutyral” or in accordance with ASTM D1396-92.

The acetalization degree of the polyvinyl acetal resin (thebutyralization degree in the case of a polyvinyl butyral resin) ispreferably greater than or equal to 60% by mole, more preferably greaterthan or equal to 63% by mole, preferably less than or equal to 85% bymole, more preferably less than or equal to 75% by mole, and furtherpreferably less than or equal to 70% by mole. When the acetalizationdegree is greater than or equal to the above lower limit, thecompatibility between the polyvinyl acetal resin and a plasticizer isheightened. When the acetalization degree is less than or equal to theabove upper limit, the reaction time required for producing thepolyvinyl acetal resin is shortened.

The acetalization degree is a value expressing the mole fractiondetermined by dividing the amount of ethylene groups to which the acetalgroup is bonded by the total amount of ethylene groups in the main chainin terms of percentage.

The acetalization degree can be calculated by a method in accordancewith JIS K6728 “Testing methods for polyvinyl butyral” or a method inaccordance with ASTM D1396-92.

In this connection, it is preferred that the content ratio of thehydroxyl group (the amount of hydroxyl groups), the acetalization degree(the butyralization degree) and the acetylation degree be calculatedfrom the results measured by a method in accordance with JIS K6728“Testing methods for polyvinyl butyral”. In the case where the polyvinylacetal resin is a polyvinyl butyral resin, it is preferred that thecontent ratio of the hydroxyl group (the amount of hydroxyl groups), theacetalization degree (the butyralization degree) and the acetylationdegree be calculated from the results measured by a method in accordancewith JIS K6728 “Testing methods for polyvinyl butyral”.

(Plasticizer)

Each of the first resin layer and the second resin layer contains aplasticizer. It is preferred that the third resin layer contain aplasticizer. The plasticizer in the first resin layer, the plasticizerin the second resin layer and the plasticizer in the third resin layerare not particularly limited. As the plasticizer, a conventionally knownplasticizer can be used. One kind of the plasticizer may be used alone,and two or more kinds thereof may be combinedly used. The plasticizer inthe first resin layer, the plasticizer in the second resin layer and theplasticizer in the third resin layer may be the same as or differentfrom one another.

Examples of the plasticizer include organic ester plasticizers such as amonobasic organic acid ester and a polybasic organic acid ester, organicphosphate plasticizers such as an organic phosphate plasticizer and anorganic phosphite plasticizer, and the like. Of these, organic esterplasticizers are preferred. It is preferred that the plasticizer be aliquid plasticizer.

The monobasic organic acid ester is not particularly limited andexamples thereof include a glycol ester obtained by the reaction of aglycol with a monobasic organic acid, and the like. Examples of theglycol include triethylene glycol, tetraethylene glycol, tripropyleneglycol, and the like. Examples of the monobasic organic acid includebutyric acid, isobutyric acid, caproic acid, 2-ethylbutyric acid,heptanoic acid, n-octylic acid, 2-ethylhexanoic acid, n-nonylic acid,decanoic acid, and the like.

The polybasic organic acid ester is not particularly limited andexamples thereof include an ester compound of a polybasic organic acidand an alcohol having a linear or branched structure of 4 to 8 carbonatoms. Examples of the polybasic organic acid include adipic acid,sebacic acid, azelaic acid, and the like.

The organic ester plasticizer is not particularly limited and examplesthereof include triethylene glycol di-2-ethylbutyrate, triethyleneglycol di-2-ethylhexanoate, triethylene glycol dicaprylate, triethyleneglycol di-n-octanoate, triethylene glycol di-n-heptanoate, tetraethyleneglycol di-n-heptanoate, dibutyl sebacate, dioctyl azelate, dibutylcarbitol adipate, ethylene glycol di-2-ethylbutyrate, 1,3-propyleneglycol di-2-ethylbutyrate, 1,4-butylene glycol di-2-ethylbutyrate,diethylene glycol di-2-ethylbutyrate, diethylene glycoldi-2-ethylhexanoate, dipropylene glycol di-2-ethylbutyrate, triethyleneglycol di-2-ethylpentanoate, tetraethylene glycol di-2-ethylbutyrate,diethylene glycol dicapryate, dihexyl adipate, dioctyl adipate, hexylcyclohexyl adipate, a mixture of heptyl adipate and nonyl adipate,diisononyl adipate, diisodecyl adipate, heptyl nonyl adipate, dibutylsebacate, oil-modified sebacic acid alkyd, a mixture of a phosphoricacid ester and an adipic acid ester, and the like. Organic esterplasticizers other than these may be used.

The organic phosphate plasticizer is not particularly limited andexamples thereof include tributoxyethyl phosphate, isodecyl phenylphosphate, triisopropyl phosphate, and the like.

It is preferred that the plasticizer be a diester plasticizerrepresented by the following formula (1).

In the foregoing formula (1), R1 and R2 each represent an organic groupwith 5 to 10 carbon atoms, R3 represents an ethylene group, anisopropylene group or an n-propylene group, and p represents an integerof 3 to 10. It is preferred that R1 and R2 in the foregoing formula (1)each be an organic group with 6 to 10 carbon atoms.

It is preferred that the plasticizer include at least one kind amongtriethylene glycol di-2-ethylhexanoate (3GO) and triethylene glycoldi-2-ethylbutyrate (3GH), and it is more preferred that the plasticizerinclude triethylene glycol di-2-ethylhexanoate.

The content of the plasticizer is not particularly limited. Relative to100 parts by mass of the whole thermoplastic resin in the interlayerfilm, the whole content of the plasticizers in the interlayer film ispreferably greater than or equal to 25 parts by mass, more preferablygreater than or equal to 30 parts by mass, preferably less than or equalto 60 parts by mass, and more preferably less than or equal to 50 partsby mass. Relative to 100 parts by mass of the thermoplastic resin in thefirst resin layer, the content of the plasticizer in the first resinlayer is preferably greater than or equal to 25 parts by mass, morepreferably greater than or equal to 30 parts by mass, further preferablygreater than or equal to 35 parts by mass, preferably less than or equalto 60 parts by mass, more preferably less than or equal to 50 parts bymass, and further preferably less than or equal to 41 parts by mass.Relative to 100 parts by mass of the thermoplastic resin in the secondresin layer, the content of the plasticizer in the second resin layer ispreferably greater than or equal to 25 parts by mass, more preferablygreater than or equal to 30 parts by mass, further preferably greaterthan or equal to 31 parts by mass, preferably less than or equal to 60parts by mass, more preferably less than or equal to 50 parts by mass,and further preferably less than or equal to 44 parts by mass. When thecontent of the plasticizer is greater than or equal to the above lowerlimit, the penetration resistance of laminated glass is furtherenhanced. When the content of the plasticizer is less than or equal tothe above upper limit, the transparency of the interlayer film isfurther enhanced.

Relative to 100 parts by mass of the thermoplastic resin in the thirdresin layer, the content of the plasticizer in the third resin layer ispreferably greater than or equal to 40 parts by mass, more preferablygreater than or equal to 45 parts by mass, preferably less than or equalto 90 parts by mass, and more preferably less than or equal to 80 partsby mass. When the content of the plasticizer is greater than or equal tothe above lower limit, the penetration resistance and the soundinsulating properties of laminated glass are further enhanced. When thecontent of the plasticizer is less than or equal to the above upperlimit, the transparency of the interlayer film is further enhanced.

Moreover, by increasing the content of the plasticizer in the firstresin layer or the content of the plasticizer in the second resin layer,it is possible to decrease the complex viscosity of each the first resinlayer or the second resin layer.

In order to allow the complex viscosity at 200° C. of the second resinlayer to be greater than or equal to 0.7 times and less than or equal to2 times the complex viscosity at 200° C. of the first resin layer, it ispreferred that the content of the plasticizer in the first resin layerand the content of the plasticizer in the second resin layer satisfy thefollowing requirement.

In order to allow the complex viscosity at 200° C. of the second resinlayer to be greater than or equal to 0.7 times and less than or equal to2 times the complex viscosity at 200° C. of the first resin layer, it ispreferred that, relative to 100 parts by mass of the thermoplastic resinin the first resin layer, the content of the plasticizer in the firstresin layer be greater than or equal to 35 parts by mass and less thanor equal to 45 parts by mass, and relative to 100 parts by mass of thethermoplastic resin in the second resin layer, the content of theplasticizer in the second resin layer be greater than or equal to 30parts by mass and less than or equal to 50 parts by mass. In particular,in the case where the thermoplastic resins used for the first resinlayer and the second resin layer are the same as each other, it ispreferred that, relative to 100 parts by mass of the thermoplastic resinin the first resin layer, the content of the plasticizer in the firstresin layer be greater than or equal to 35 parts by mass and less thanor equal to 41 parts by mass, and relative to 100 parts by mass of thethermoplastic resin in the second resin layer, the content of theplasticizer in the second resin layer be greater than or equal to 31parts by mass and less than or equal to 44 parts by mass.

(Inorganic Particles)

The second resin layer contains inorganic particles. The inorganicparticle is not particularly limited. As the inorganic particle, aconventionally known inorganic particle can be used. One kind of theinorganic particle may be used alone, and two or more kinds thereof maybe combinedly used.

Examples of the inorganic particles include calcium carbonate particles,alumina particles, kaolin clay particles, calcium silicate particles,magnesium oxide particles, magnesium hydroxide particles, aluminumhydroxide particles, magnesium carbonate particles, talc particles,feldspar powder particles, mica particles, barite particles, bariumcarbonate particles, titanium oxide particles, silica particles, glassbeads, and the like.

It is preferred that the inorganic particles include at least one kindselected from the group consisting of calcium carbonate particles,titanium oxide particles and silica particles, and it is more preferredthat the inorganic particles include calcium carbonate particles. By theuse of these preferred inorganic particles, laminated glass furtherexcellent in the appearance design property in which the appearanceirregularity is suppressed at the time of allowing light to betransmitted therethrough is obtained.

The average particle diameter of the inorganic particles is preferablygreater than or equal to 1 μm, preferably less than or equal to 100 μm,and more preferably less than or equal to 50 μm. The average particlediameter refers to the weight average particle diameter. The averageparticle diameter can be measured by a dynamic light scattering methodusing a light scattering measurement apparatus and an Ar laser as thelight source. Examples of the light scattering measurement apparatusinclude “DLS-6000AL” available from Otsuka Electronics Co., Ltd., andthe like.

It is preferred that the content of the inorganic particles beappropriately adjusted so that the parallel light transmittance in aportion of the dark color part of laminated glass such as the laminatedglass C, the laminated glass CA, the laminated glass CB, the laminatedglass CC, the laminated glass CD, the laminated glass CE, the laminatedglass CX and the laminated glass CY is less than or equal to 30%, andthe parallel light transmittance in a portion of the gradation part oflaminated glass such as the laminated glass C, the laminated glass CA,the laminated glass CB, the laminated glass CC, the laminated glass CD,the laminated glass CE, the laminated glass CX and the laminated glassCY is continuously increased from the dark color part side to thetransparent part side. In 100% by mass of the whole second resin layer,the content of the inorganic particles is preferably greater than orequal to 0.3% by mass, more preferably greater than or equal to 0.5% bymass, further preferably greater than or equal to 2% by mass, especiallypreferably greater than or equal to 3% by mass, preferably less than orequal to 25% by mass, and more preferably less than or equal to 5% bymass. When the content of the inorganic particles is greater than orequal to the above lower limit and less than or equal to the above upperlimit, an interlayer film moderately colored is obtained, and it ispossible to easily control the value of the parallel light transmittanceof the laminated glass within a suitable range. Moreover, laminatedglass further excellent in the appearance design property in which theappearance irregularity is more hardly generated at the time of allowinglight to be transmitted therethrough is obtained. Moreover, byincreasing the content of the inorganic particles in the second resinlayer, it is possible to increase the complex viscosity of the secondresin layer.

The area density of inorganic particles in the thickest portion of thesecond resin layer of the first interlayer film for laminated glassincluding the above-mentioned first configuration is preferably greaterthan or equal to 3 g/m², more preferably greater than or equal to 15g/m², preferably less than or equal to 70 g/m², and more preferably lessthan or equal to 25 g/m². Examples of the measuring method for the areadensity of inorganic particles in the thickest portion of the secondresin layer of the first interlayer film for laminated glass includingthe above-mentioned first configuration include a method describedbelow.

The interlayer film is cut in the thickness direction so that thethickest portion of the second resin layer is situated at the center ofthe resulting sample to obtain a sample with a rectangular planar shape.The resulting sample is allowed to have a length of the short side of 1cm, a thickness corresponding to the thickness of the interlayer film,and a length of the long side that the mass of the sample becomes 1 g.The long-side direction in the resulting sample is a directionorthogonal to the direction connecting the thickest portion of thesecond resin layer and a portion of the transparent part situatednearest to the thickest portion of the second resin layer. Provided thatthe thickest portion of the second resin layer is situated at the endpart or near the end part of the second resin layer and a sample inwhich the thickest portion of the second resin layer is situated at thecenter in the long-side direction of the resulting sample fails to beobtained, one end in the long-side direction of the sample is alignedwith the end part of the second resin layer to obtain a sample. Giventhat the thickest portion of the second resin layer is situated at theend part or near the end part of the second resin layer and a sample inwhich the thickest portion of the second resin layer is situated at thecenter in the short-side direction of the resulting sample fails to beobtained, one end in the short-side direction of the sample is alignedwith the end part of the second resin layer to obtain a sample.

The area density of inorganic particles in the portion where the totalthickness of the second resin layers is the thickest in the secondinterlayer film for laminated glass including the above-mentioned secondconfiguration is preferably greater than or equal to 2 g/m², morepreferably greater than or equal to 4 g/m², preferably less than orequal to 23 g/m², and more preferably less than or equal to 9 g/m².Examples of the measuring method for the area density of inorganicparticles in the portion where the total thickness of the second resinlayers is the thickest in the second interlayer film for laminated glassincluding the above-mentioned second configuration include a methoddescribed below.

The interlayer film is cut in the thickness direction so that theportion where the total thickness of the second resin layers is thethickest is situated at the center of the resulting sample to obtain asample with a rectangular planar shape. The resulting sample is allowedto have a length of the short side of 1 cm, a thickness corresponding tothe thickness of the interlayer film, and a length of the long side thatthe mass of the sample becomes 1 g. The long-side direction in theresulting sample is a direction orthogonal to the direction connectingthe portion where the total thickness of the second resin layers is thethickest and a portion of the transparent part situated nearest to theportion where the total thickness of the second resin layers is thethickest. Provided that the portion where the total thickness of thesecond resin layers is the thickest is situated at the end part or nearthe end part of the second resin layer and a sample in which the portionwhere the total thickness of the second resin layers is the thickest issituated at the center in the long-side direction of the resultingsample fails to be obtained, one end in the long-side direction of thesample is aligned with the end part of the second resin layer to obtaina sample. Given that the portion where the total thickness of the secondresin layers is the thickest is situated at the end part or near the endpart of the second resin layer and a sample in which the portion wherethe total thickness of the second resin layers is the thickest issituated at the center in the short-side direction of the resultingsample fails to be obtained, one end in the short-side direction of thesample is aligned with the end part of the second resin layer to obtaina sample.

The area density of inorganic particles in the portion where the totalthickness of the second resin layers is the thinnest in the secondinterlayer film for laminated glass including the above-mentioned secondconfiguration is preferably greater than or equal to 0.5 g/m², morepreferably greater than or equal to 1.5 g/m², preferably less than orequal to 2.5 g/m², and more preferably less than or equal to 2.0 g/m².Examples of the measuring method for the area density of inorganicparticles in the portion where the total thickness of the second resinlayers is the thinnest in the second interlayer film for laminated glassincluding the above-mentioned second configuration include a methoddescribed below.

The interlayer film is cut in the thickness direction so that theportion where the total thickness of the second resin layers is thethinnest is situated at the center of the resulting sample to obtain asample with a rectangular planar shape. The resulting sample is allowedto have a length of the short side of 1 cm, a thickness corresponding tothe thickness of the interlayer film, and a length of the long side thatthe mass of the sample becomes 1 g. The long-side direction in theresulting sample is a direction orthogonal to the direction connectingthe portion where the total thickness of the second resin layers is thethinnest and a portion of the dark color part situated nearest to theportion where the total thickness of the second resin layers is thethinnest. Provided that the portion where the total thickness of thesecond resin layers is the thinnest is situated at the end part or nearthe end part of the second resin layer and a sample in which the portionwhere the total thickness of the second resin layers is the thinnest issituated at the center in the long-side direction of the resultingsample fails to be obtained, one end in the long-side direction of thesample is aligned with the end part of the second resin layer to obtaina sample. Given that the portion where the total thickness of the secondresin layers is the thinnest is situated at the end part or near the endpart of the second resin layer and a sample in which the portion wherethe total thickness of the second resin layers is the thickest issituated at the center in the short-side direction of the resultingsample fails to be obtained, one end in the short-side direction of thesample is aligned with the end part of the second resin layer to obtaina sample.

To 1 g of the obtained sample, 18 mL of an aqueous 70% by mass nitricacid solution is added, and the sample is held in place for 30 minutesat 200° C. using a microwave sample pretreatment apparatus (“ETHOS One”available from Milestone General K. K.) to be thermally decomposed,after which the sample is made up to a prescribed volume with ultrapurewater having a specific resistance of 18.2 MΩ·cm under a condition of25° C. to obtain a test liquid. Next, by means of a high frequencyinductively coupled plasma emission spectrometer (“ICPE-9000” availablefrom SHIMADZU CORPORATION), a metal element or the silicon constitutinginorganic particles in the test liquid is quantitatively analyzed, andfrom the obtained value of the metal element or silicon content, thearea density of inorganic particles is calculated.

It is preferred that the first resin layer do not contain inorganicparticles. Provided that the laminated glass C satisfies the requirementon the parallel light transmittance, the first resin layer may containinorganic particles. It is preferred that the content of inorganicparticles in 100% by mass of the first resin layer be smaller than thecontent of inorganic particles in 100% by mass of the second resinlayer. The content of inorganic particles in 100% by mass of the firstresin layer is preferably less than 3% by mass, more preferably lessthan 2% by mass, further preferably less than 0.5% by mass, andespecially preferably less than 0.3% by mass. Since the smaller thecontent of inorganic particles in 100% by mass of the first resin layeris, the smaller the existing amount of inorganic particles at thesurface side of the interlayer film becomes, the interlayer film and thelaminated glass member are more strongly bonded together.

(Other Ingredients)

Each of the interlayer film, the first resin layer and the second resinlayer may include additives such as heat shielding particles, alightshielding agent, a coloring agent, an ultraviolet ray absorber, anoxidation inhibitor, an adhesive force regulating agent, a lightstabilizer, a flame retardant, an antistatic agent, amoisture-resistance improving agent, a heat ray reflecting agent, and aheat ray absorber, as necessary. One kind of the additive may be usedalone, and two or more kinds thereof may be combinedly used.

The heat shielding particle means a particle capable of absorbinginfrared rays. Specific examples of the heat shielding particles includemetal oxide particles such as aluminum-doped tin oxide particles,indium-doped tin oxide particles, antimony-doped tin oxide particles(ATO particles), gallium-doped zinc oxide particles (GZO particles),indium-doped zinc oxide particles (IZO particles), aluminum-doped zincoxide particles (AZO particles), niobium-doped titanium oxide particles,tungsten oxide particles, tin-doped indium oxide particles (ITOparticles), tin-doped zinc oxide particles and silicon-doped zinc oxideparticles, lanthanum hexaboride (LaB₆) particles, and the like.Moreover, as the heat shielding particles, zinc antimonate, ceriumhexaboride, gold powder, silver powder, platinum powder, aluminumpowder, and the like may be used.

Examples of the light shielding agent include carbon black, a red ironoxide, and the like.

Examples of the coloring agent include a pigment, a dye, and the like.It is preferred that the coloring agent be a pigment. Examples of thepigment include a dark reddish-brown mixed pigment prepared by mixingcarbon black as a black pigment, a red pigment (C. I. Pigment red), ablue pigment (C. I. Pigment blue) and a yellow pigment (C. I. Pigmentyellow), and the like.

Examples of the ultraviolet ray absorber include a malonic acid estercompound, an oxanilide compound, a benzotriazole compound, abenzophenone compound, a triazine compound, a benzoate compound, ahindered amine compound, and the like. Of these, a benzotriazolecompound is preferred.

Examples of the oxidation inhibitor include t-butylhydroxytoluene,tetrakis-[methylene-3-(3′,5′-di-t-butyl-4′-hydroxyphenyl)propionate]methane,and the like.

Examples of the adhesive force regulating agent include an alkali metalsalt of each of an organic acid and an inorganic acid, an alkaline earthmetal salt of each of an organic acid and an inorganic acid, a silanecoupling agent, a modified silicone oil, and the like.

(Other Details of Interlayer Film for Laminated Glass)

The production method of the interlayer film for laminated glassaccording to the present invention is not particularly limited. As theproduction method of the interlayer film, a conventionally known methodcan be employed. Examples of the production method of the interlayerfilm include a production method of kneading respective ingredientsdescribed above and molding an interlayer film, and the like. Aproduction method of extrusion-molding is preferred because the methodis suitable for continuous production. Of these, in the case ofproducing the above-mentioned first interlayer film for laminated glassincluding the above-mentioned first configuration, a method of supplyingrespective ingredients to be contained in the above-mentioned secondresin layer (a second resin composition for forming the second resinlayer) to a main extruder, supplying respective ingredients for formingthe above-mentioned first resin layer (a first resin composition forforming the first resin layer) to a sub-extruder, and attaching amulti-layer feed block to the tip end of each of the main extruder andthe sub-extruder to perform the coextrusion is preferred. Moreover, inthe case of producing the above-mentioned second interlayer film forlaminated glass including the above-mentioned second configuration, amethod of supplying respective ingredients to be contained in theabove-mentioned first resin layer (a first resin composition for formingthe first resin layer) to a main extruder, supplying respectiveingredients for forming the above-mentioned second resin layer (a secondresin composition for forming the second resin layer) to a sub-extruder,and attaching a multi-layer feed block to the tip end of each of themain extruder and the sub-extruder to perform the coextrusion ispreferred. By the production method using the multi-layer feed block,the generation of a color streak which has been sometimes caused at thetime of preparing an interlayer film is further suppressed.

Moreover, at the time of obtaining the interlayer film, it is preferredthat a dispersion be prepared by dispersing inorganic particles togetherwith a dispersing agent and the like blended as necessary in aplasticizer, the dispersion and other ingredients (preferably athermoplastic resin) be kneaded, and the kneaded product be formed intoan interlayer film. By using such a dispersion, the dispersibility ofinorganic particles in the interlayer film is improved, and the additioneffect of inorganic particles is further uniformly developed in theinterlayer film.

The method for kneading is not particularly limited. Examples of thismethod include a method using an extruder, a plastograph, a kneader, abanbury mixer, a calender roll, or the like. Of these, a method using anextruder is preferred and a method using a twin screw extruder is morepreferred because the methods are suitable for continuous production.

(Laminated Glass)

FIG. 11 shows an example of laminated glass prepared with the interlayerfilm for laminated glass shown in FIG. 1 represented as across-sectional view.

The laminated glass 21 shown in FIG. 11 is provided with a firstlaminated glass member 22, a second laminated glass member 23 and aninterlayer film 1 arranged between the first laminated glass member 22and the second laminated glass member 23. The interlayer film 1 issandwiched between the first laminated glass member 22 and the secondlaminated glass member 23. The first laminated glass member 22 islayered on a first surface (one surface) of the interlayer film 1. Thesecond laminated glass member 23 is layered on a second surface (theother surface) opposite to the first surface of the interlayer film 1.

Examples of the first and second laminated glass members include a glassplate and a PET (polyethylene terephthalate) film and the like. As thelaminated glass, laminated glass in which an interlayer film issandwiched between a glass plate and a PET film or the like, as well aslaminated glass in which an interlayer film is sandwiched between twoglass plates, is included. Laminated glass is a laminate provided with aglass plate, and it is preferred that at least one glass plate be used.

Examples of the glass plate include a sheet of inorganic glass and asheet of organic glass. Examples of the inorganic glass include floatplate glass, heat ray absorbing plate glass, heat ray-reflecting plateglass, polished plate glass, figured glass, net-reinforced plate glass,wired plate glass, clear glass, and the like. The organic glass issynthetic resin glass substituted for inorganic glass. Examples of theorganic glass include a polycarbonate plate, a poly (meth) acrylic resinplate, and the like. Examples of the poly(meth)acrylic resin plateinclude a polymethyl (meth)acrylate plate, and the like.

Although the thickness of the laminated glass member is not particularlylimited, the thickness is preferably greater than or equal to 1 mm,preferably less than or equal to 5 mm, and more preferably less than orequal to 3 mm. Moreover, in the case where the laminated glass member isa glass plate, the thickness of the glass plate is preferably greaterthan or equal to 1 mm, preferably less than or equal to 5 mm, and morepreferably less than or equal to 3 mm. In the case where the laminatedglass member is a PET film, the thickness of the PET film is preferablygreater than or equal to 0.03 mm and preferably less than or equal to0.5 mm.

The production method of the laminated glass is not particularlylimited. For example, the interlayer film is sandwiched between thefirst and second laminated glass members and the air remaining betweeneach of the first and second laminated glass members and the interlayerfilm is removed by allowing the members to pass through a pressing rollor by putting the members into a rubber bag and allowing the contents tobe sucked under reduced pressure. Afterward, the members arepreliminarily bonded together at about 70 to 110° C. to obtain alaminate. Next, by putting the laminate into an autoclave or by pressingthe laminate, the members are press-bonded together at about 120 to 150°C. and under a pressure of 1 to 1.5 MPa. In this way, laminated glasscan be obtained.

The interlayer film and the laminated glass can be used for automobiles,railway vehicles, aircraft, ships, buildings and the like. It ispreferred that the interlayer film be an interlayer film forconstruction or for vehicles. It is preferred that the laminated glassbe laminated glass for construction or for vehicles.

Hereinafter, the present invention will be described in more detail withreference to examples. The present invention is not limited only to thefollowing examples.

EXAMPLE 1

(Preparation of First Resin Composition for Forming First Resin Layer A(First Surface Layer) and First Resin Layer B (Second Surface Layer))

Polyvinyl butyral A (the acetylation degree of 1% by mole, thebutyralization degree of 69% by mole, the content of the hydroxyl groupof 30% by mole) obtained by acetalizing polyvinyl alcohol (the averagepolymerization degree of 1700) with n-butyraldehyde was prepared. To 100parts by mass of this Polyvinyl butyral A, 39 parts by mass oftriethylene glycol-di-2-ethylhexanoate (a plasticizer, 3GO) was addedand thoroughly kneaded with a mixing roll to obtain a first resincomposition.

(Preparation of Second Resin Composition for Forming Second Resin Layer(Intermediate Layer))

To 100 parts by mass of the Polyvinyl butyral A, 40 parts by mass oftriethylene glycol-di-2-ethylhexanoate (a plasticizer, 3GO) and calciumcarbonate particles (inorganic particles, the weight average particlediameter of 5.0 μm) in an amount that the content thereof in 100% bymass of the resulting resin composition becomes 5.9% by mass were addedand thoroughly kneaded with a mixing roll to obtain a second resincomposition.

(Preparation of Interlayer Film for Laminated Glass)

The second resin composition was supplied to a main extruder. Moreover,the first resin composition was supplied to a sub-extruder. By attachinga multi-layer feed block to the tip end of each of the main extruder andthe sub-extruder to perform the coextrusion, an interlayer film havingtwo first resin layers and a second resin layer embedded between the twofirst resin layers in the dark color part and the gradation part andhaving a first resin layer in the transparent part was obtained. In thisconnection, with regard to the boundary between the dark color part andthe gradation part in the obtained interlayer film, at the time ofpreparing laminated glass described below and measuring the parallellight transmittance, a portion where the parallel light transmittance is30% is defined as the boundary, an area where the parallel lighttransmittance is less than or equal to 30% is defined as the dark colorpart, and an area where the parallel light transmittance is greater than30% and less than 60% is defined as the gradation part. The thicknessesof respective layers in the obtained interlayer film are shown in thefollowing Table 1.

In this connection, with regard to the thicknesses of respective layersin the interlayer film, the interlayer film was cut with a sharp razorblade so that the cross-section of the dark color part, the gradationpart and the transparent part in the layered direction including thedark color part, the gradation part and the transparent part is exposed,after which the exposed cross-section of the interlayer film wasobserved with a digital microscope (“DSX500” available from OlympusCorporation) to measure the thicknesses of respective layers in theinterlayer film with a micro gauge. Moreover, the shape of the exposedcross-section of the interlayer film was the shape corresponding to thatin FIG. 1 (the shape similar to that in FIG. 1).

Moreover, the area density of inorganic particles in the thickestportion of the second resin layer of the interlayer film was measured inthe following manner.

The interlayer film was cut in the thickness direction so that thethickest portion of the second resin layer was situated at the center ofthe resulting sample to obtain a sample with a rectangular planar shape.The resulting sample was allowed to have a length of the short side of 1cm, a thickness corresponding to the thickness of the interlayer film,and a length of the long side that the mass of the sample becomes 1 g.The long-side direction in the resulting sample was a directionorthogonal to the direction connecting the thickest portion of thesecond resin layer and a portion of the transparent part situatednearest to the thickest portion of the second resin layer.

To the obtained sample was added 18 mL of an aqueous 70% by mass nitricacid solution, and the sample was held in place for 30 minutes at 200°C. using a microwave sample pretreatment apparatus (“ETHOS One”available from Milestone General K. K.) to be thermally decomposed,after which the sample was made up to a prescribed volume with ultrapurewater having a specific resistance of 18.2 MΩ·cm under a condition of25° C. to obtain a test liquid. Next, by means of a high frequencyinductively coupled plasma emission spectrometer (“ICPE-9000” availablefrom SHIMADZU CORPORATION), the calcium in the test liquid wasquantitatively analyzed, and from the obtained value of the calciumcontent, the area density of calcium carbonate particles was calculated.

(Preparation of Laminated Glass)

Two sheets of clear glass (100 cm in longitudinal length by 30 cm intransversal length by 2.5 mm in thickness) in accordance with JIS R3202(1996) were prepared. The above-mentioned interlayer film obtained wassandwiched between the two sheets of clear glass from both ends toobtain a laminate. This laminate was put into a rubber bag and degassedfor 20 minutes at a degree of vacuum of 2.6 kPa, after which thelaminate was transferred into an oven while being degassed, andfurthermore, held in place for 30 minutes at 90° C. and pressed undervacuum to subject the laminate to preliminary press-bonding. Thepreliminarily press-bonded laminate was subjected to press-bonding for20 minutes under conditions of 135° C. and a pressure of 1.2 MPa in anautoclave to obtain a sheet of laminated glass.

Examples 2 to 12 and Comparative Example 1

An interlayer film and a sheet of laminated glass were prepared in thesame manner as that in Example 1 except that the content of calciumcarbonate particles was set to that listed in the following Tables 1 and2, and the lengths and thicknesses of respective layers in the resultinginterlayer film were set to those listed in the following Tables 1 and2, at the time of preparing the interlayer film.

Comparative Examples 2, 3

An interlayer film and a sheet of laminated glass were prepared in thesame manner as that in Example 1 except that the multi-layer feed blockwas modified to obtain the interlayer film which has a three-layerstructure allowing a first resin layer, a second resin layer and a firstresin layer to be layered in this order in the thickness direction overthe whole area of the interlayer film and does not have a transparentlayer, and the thicknesses of respective layers in the resultinginterlayer film were set to those listed in the following Table 2, atthe time of preparing the interlayer film. In this connection, withregard to the boundary between the dark color part and the gradationpart in the interlayer film obtained in Examples 2 to 12, at the time ofmeasuring the parallel light transmittance of the sheet of laminatedglass obtained in Examples 2 to 12, a portion where the parallel lighttransmittance is 30% is defined as the boundary, an area where theparallel light transmittance is less than or equal to 30% is defined asthe dark color part, and an area where the parallel light transmittanceis greater than 30% and less than 60% is defined as the gradation part.Moreover, with regard to the boundary between the gradation part and thetransparent part in the interlayer film obtained in Examples 8 to 12, atthe time of measuring the parallel light transmittance of the sheet oflaminated glass obtained in Examples 8 to 12, a portion where theparallel light transmittance is 60% is defined as the boundary, an areawhere the parallel light transmittance is greater than 30% and less than60% is defined as the gradation part, and an area where the parallellight transmittance is greater than or equal to 60% is defined as thetransparent part. Moreover, the sheet of laminated glass obtained inComparative Example 1 did not have an area where the parallel lighttransmittance is less than or equal to 30%, that is, a dark color part.In this connection, in Comparative Example 1, at the time of measuringthe parallel light transmittance of the sheet of laminated glassobtained in Comparative Example 1, an area where the parallel lighttransmittance is greater than or equal to 60% is defined as thetransparent part.

Examples 13 to 25, Comparative Examples 4, 5

An interlayer film and a sheet of laminated glass were prepared in thesame manner as that in Example 1 except that the shape of thecross-section of the interlayer film was changed to that listed in thefollowing Tables 3 and 4, the content of calcium carbonate particles andthe content of the plasticizer were set to those listed in the followingTables 3 and 4, and the lengths and thicknesses of respective layers inthe resulting interlayer film were set to those listed in the followingTables 3 and 4, at the time of preparing the interlayer film. In thisconnection, in Examples 11 to 16 and Comparative Example 7, the shape ofthe exposed cross-section of the interlayer film was the shapecorresponding to that in FIG. 4 (the shape similar to that in FIG. 4).In Examples 17 to 22 and Comparative Examples 8 and 9, the shape of theexposed cross-section of the interlayer film was the shape correspondingto that in FIG. 5 (the shape similar to that in FIG. 5). In thisconnection, with regard to the boundary between the dark color part andthe gradation part in the interlayer film obtained in Examples 13 to 25,at the time of measuring the parallel light transmittance of the sheetof laminated glass obtained in Examples 13 to 25, a portion where theparallel light transmittance is 30% is defined as the boundary, an areawhere the parallel light transmittance is less than or equal to 30% isdefined as the dark color part, and an area where the parallel lighttransmittance is greater than 30% and less than 60% is defined as thegradation part. Moreover, with regard to the boundary between thegradation part and the transparent part in the interlayer film obtainedin Examples 13 to 25, at the time of measuring the parallel lighttransmittance of the sheet of laminated glass obtained in Examples 13 to25, a portion where the parallel light transmittance is 60% is definedas the boundary, an area where the parallel light transmittance isgreater than 30% and less than 60% is defined as the gradation part, andan area where the parallel light transmittance is greater than or equalto 60% is defined as the transparent part. Moreover, the sheets oflaminated glass obtained in Comparative Example 4 and ComparativeExample 5 did not have an area where the parallel light transmittance isless than or equal to 30%, that is, a dark color part. In thisconnection, in Comparative Example 4 and Comparative Example 5, at thetime of measuring the parallel light transmittance of the sheet oflaminated glass obtained in Comparative Example 4 and ComparativeExample 5, an area where the parallel light transmittance is greaterthan or equal to 60% is defined as the transparent part.

Example 26

(Preparation of First Resin Composition for Forming First Resin Layer(Intermediate Layer))

Polyvinyl butyral A (the acetylation degree of 1% by mole, thebutyralization degree of 69% by mole, the content of the hydroxyl groupof 30% by mole) obtained by acetalizing polyvinyl alcohol (the averagepolymerization degree of 1700) with n-butyraldehyde was prepared. To 100parts by mass of this Polyvinyl butyral A, 39 parts by mass oftriethylene glycol-di-2-ethylhexanoate (a plasticizer, 3GO) was addedand thoroughly kneaded with a mixing roll to obtain a first resincomposition.

(Preparation of Second Resin Composition for Forming Second Resin LayerA (First Surface Layer) and Second Resin Layer B (Second Surface Layer))

To 100 parts by mass of the Polyvinyl butyral A, 40 parts by mass oftriethylene glycol-di-2-ethylhexanoate (a plasticizer, 3GO) and calciumcarbonate particles (inorganic particles, the weight average particlediameter of 5.0 μm) in an amount that the content thereof in 100% bymass of the resulting resin composition becomes 0.679% by mass wereadded and thoroughly kneaded with a mixing roll to obtain a second resincomposition.

(Preparation of Interlayer Film for Laminated Glass)

The first resin composition was supplied to a main extruder. Moreover,the second resin composition was supplied to a sub-extruder. Byattaching a multi-layer feed block to the tip end of each of the mainextruder and the sub-extruder to perform the coextrusion, an interlayerfilm having two second resin layers and a first resin layer embeddedbetween the two second resin layers in the transparent part and thegradation part and having a second resin layer in the dark color partwas obtained. The thicknesses of respective layers in the obtainedinterlayer film are shown in the following Table 5.

In this connection, with regard to the thicknesses of respective layersin the interlayer film, the interlayer film was cut with a sharp razorblade so that the cross-section of the dark color part, the gradationpart and the transparent part in the layered direction including thedark color part, the gradation part and the transparent part is exposed,after which the exposed cross-section of the interlayer film wasobserved with a digital microscope (“DSX500” available from OlympusCorporation) to measure the thicknesses of respective layers in theinterlayer film with a micro gauge. Moreover, the shape of the exposedcross-section of the interlayer film was the shape corresponding to thatin FIG. 7 (the shape similar to that in FIG. 7).

Moreover, the area density of inorganic particles in the portion wherethe total thickness of the two second resin layers is the thickest inthe interlayer film was measured in the following manner.

The interlayer film was cut in the thickness direction so that theportion where the total thickness of the two second resin layers is thethickest was situated at the center of the resulting sample to obtain asample with a rectangular planar shape. The resulting sample was allowedto have a length of the short side of 1 cm, a thickness corresponding tothe thickness of the interlayer film, and a length of the long side thatthe mass of the sample becomes 1 g. The long-side direction in theresulting sample was a direction orthogonal to the direction connectingthe thickest portion of the two second resin layers and a portion of thetransparent part situated nearest to the thickest portion of the twosecond resin layers.

To the obtained sample was added 18 mL of an aqueous 70% by mass nitricacid solution, and the sample was held in place for 30 minutes at 200°C. using a microwave sample pretreatment apparatus (“ETHOS One”available from Milestone General K. K.) to be thermally decomposed,after which the sample was made up to a prescribed volume with ultrapurewater having a specific resistance of 18.2 MΩ·cm under a condition of25° C. to obtain a test liquid. Next, by means of a high frequencyinductively coupled plasma emission spectrometer (“ICPE-9000” availablefrom SHIMADZU CORPORATION), the calcium in the test liquid wasquantitatively analyzed, and from the obtained value of the calciumcontent, the area density of calcium carbonate particles was calculated.

Moreover, the area density of inorganic particles in the portion wherethe total thickness of the two second resin layers is the thinnest inthe interlayer film was measured in the following manner.

The interlayer film was cut in the thickness direction so that theportion where the total thickness of the two second resin layers is thethinnest was situated at the center of the resulting sample to obtain asample with a rectangular planar shape. The resulting sample was allowedto have a length of the short side of 1 cm, a thickness corresponding tothe thickness of the interlayer film, and a length of the long side thatthe mass of the sample becomes 1 g. The long-side direction in theresulting sample was a direction orthogonal to the direction connectingthe thinnest portion of the two second resin layers and a portion of thedark color part situated nearest to the thinnest portion of the twosecond resin layers. The obtained sample was quantitatively analyzed forthe calcium in the same procedure as that for the measurement of thearea density at the portion where the total thickness of the two secondresin layers is the thinnest, and from the obtained value of the calciumcontent, the area density of calcium carbonate particles was calculated.

(Evaluation)

(1) Parallel Light Transmittance (Tv)

The parallel light transmittance (Tv) was measured in accordance withJIS R3106 (1998). The obtained laminated glass was installed on thelight path between a light source and an integrating sphere, in parallelto the normal line of the optical axis and at a point apart from theintegrating sphere by 13 cm so that only the transmitted parallel lightwas received by the integrating sphere using a spectrophotometer(“U-4100” available from Hitachi High-Technologies Corporation). Thespectral transmittance was measured in this state. The visible lighttransmittance calculated from the obtained spectral transmittance wasdefined as the parallel light transmittance. The parallel lighttransmittance of the laminated glass obtained in each of Examples wasless than or equal to 30% in a portion of the dark color part and wasgreater than or equal to 60% in a portion of the transparent part. Amongvalues of the obtained parallel light transmittance, the minimum valueof the parallel light transmittance in a portion of the dark color partand the maximum value of the parallel light transmittance in a portionof the transparent part are shown in Tables 1 to 5. In this connection,since the sheets of laminated glass obtained in Comparative Example 1,Comparative Example 4 and Comparative Example 5 do not have a dark colorpart, the minimum values of the parallel light transmittance of theobtained laminated glass are shown in the columns for the parallel lighttransmittance of the dark color part in Table 2, Table 3 and Table 4.

(2) Total Light Transmittance (TvD)

The total light transmittance (TvD) was measured in accordance with JISR3106 (1998). The obtained laminated glass was installed in parallel toand brought into close contact with an opening part of an integratingsphere so that all light rays transmitted were received by theintegrating sphere using a spectrophotometer (“U-4100” available fromHitachi High-Technologies Corporation) to measure the spectraltransmittance. The visible light transmittance calculated from theobtained spectral transmittance was defined as the total lighttransmittance. Among values of the obtained total light transmittance,the minimum value of the total light transmittance in the dark colorpart and the maximum value of the total light transmittance in thetransparent part are shown in Tables 1 to 5. In this connection, sincethe sheets of laminated glass obtained in Comparative Example 1,Comparative Example 4 and Comparative Example 5 do not have a dark colorpart, the minimum values of the total light transmittance of theobtained laminated glass are shown in the columns for the minimum valueof the total light transmittance of the dark color part in Table 2,Table 3 and Table 4.

(3) Evaluation of Color Irregularity of Gradation—Visual Observation

The obtained laminated glass was arranged on a light table, and aportion of the gradation part of the laminated glass in a state of beingirradiated with light from the fluorescent lamp in the light table wasvisually observed for the gradation pattern from the opposite side ofthe light source. By the above-mentioned observation method, 10respondents observed the obtained laminated glass, and the colorirregularity of the gradation determined by the visual observation wasevaluated according to the following criteria. Furthermore, a white filmon which a lattice pattern of 1 cm square is printed was arrangedbetween the laminated glass and the light table, the laminated glass wasarranged at a distance of 1.5 cm from the film parallel to the laminatedglass in the thickness direction of the laminated glass, and thelaminated glass in a state of being irradiated with light from thefluorescent lamp from the upper side of the sheet of laminated glass wasobserved for the gradation pattern.

[Criteria for Judgment in Color Irregularity of Gradation by VisualObservation]

Two circles: There is no color streak: The number of respondents whojudged that there are a few color streaks is less than or equal to 2.

Circle: There is almost no color streak: The number of respondents whojudged that there are a few color streaks is greater than or equal to 3and less than or equal to 4.

X mark: There are color streaks: The number of respondents who judgedthat there are a few color streaks is greater than or equal to 5.

(4) Evaluation of Color Irregularity of Gradation TransmittanceMeasurement

The obtained laminated glass was measured for the parallel lighttransmittance (Tv) and the total light transmittance (TvD) at 1-cmintervals in a linear direction from the dark color part side to thetransparent part side in a portion of the gradation part of thelaminated glass. The color irregularity of the gradation determined bythe transmittance measurement was evaluated according to the followingcriteria.

[Criteria for Judgment in Color Irregularity of Gradation byTransmittance Measurement]

Circle: Along the direction from the dark color part side to thetransparent part side, the Tv value and the TvD value are continuouslydecreased.

X mark: Along the direction from the dark color part side to thetransparent part side, the Tv value and the TvD value are notcontinuously decreased.

(5) Evaluation of Parallel Light Transmittance of Laminated Glass

The parallel light transmittance of the obtained laminated glass wasevaluated according to the following criteria.

Circle: The interlayer film has a dark color part, a gradation part anda transparent part, the parallel light transmittance in a portion of thedark color part of the laminated glass is less than or equal to 30%, theparallel light transmittance in a portion of the gradation part of thelaminated glass is continuously increased from the dark color part sideto the transparent part side, and the parallel light transmittance in aportion of the transparent part of the laminated glass is greater thanor equal to 60%.

X mark: The laminated glass does not satisfy the criteria for judgmentof the Circle.

(6) Measurement of Complex Viscosity

The complex viscosities of the first resin layer and the second resinlayer of the obtained interlayer film for laminated glass were measuredaccording to the following procedure. With regard to the obtainedinterlayer film for laminated glass, at the end of 1 hour after beingformed into a film, the first resin layer and the second resin layerwere peeled off from each other and the first resin layer was removed.In a molding flask (2 cm in longitudinal length by 2 cm in transversallength by 0.76 mm in thickness) arranged between two sheets ofpolyethylene terephthalate (PET) films, 1 g of the first resin layerpeeled off was placed and preheated for 10 minutes at a temperature of150° C. and under a pressure of 0 kg/cm², and then press-molded for 15minutes under a pressure of 80 kg/cm². Afterward, in a hand pressmachine previously set to 20° C., the press-molded first resin layer wasinstalled and pressed for 10 minutes at 10 MPa to be cooled. Then, fromthe molding flask arranged between the two sheets of PET films, onesheet of the PET film was peeled off, and the press-molded product wasstored for 24 hours in a constant-temperature and constant-humiditychamber (a humidity of 30% (±3%), a temperature of 23° C.), and thenmeasured for the viscoelasticity, using the ARES-G2 available from TAInstruments Japan Inc., in accordance with JIS K7244-10 (IS06721-10) tomeasure the complex viscosity. As a jig used at the time of theviscoelasticity measurement, a parallel plate with a diameter of 8 mmwas used. Moreover, the viscoelasticity measurement was performed underconditions of a frequency of 1 Hz and a strain of 8% at the measurementtemperature of 200° C. The obtained complex viscosity was read as avalue of the complex viscosity of the first resin layer at 200° C.Moreover, the complex viscosity of the second resin layer was measuredin the same manner.

The results are shown in the following Tables 1 to 5.

TABLE 1 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Ex. 1 2 3 4 5 6 7 8 IngredientsFirst resin layer A Thermoplastic resin Parts by mass 100 100 100 100100 100 100 100 to be blended (first surface layer) Plasticizer Parts bymass 39 39 39 39 39 39 39 39 Calcium carbonate % by mass 0 0 0 0 0 0 00.24 Second resin layer Thermoplastic resin Parts by mass 100 100 100100 100 100 100 100 (intermediate layer) Plasticizer Parts by mass 40 4040 40 40 40 40 40 Calcium carbonate % by mass 5.9 5.7 7.0 20.0 1.8 16.52.8 5.9 Area density g/m² 19.2 17.5 21.7 59.9 5.4 19.2 19.2 19.2 Firstresin layer B Thermoplastic resin Parts by mass 100 100 100 100 100 100100 100 (second surface layer Plasticizer Parts by mass 39 39 39 39 3939 39 39 Calcium carbonate % by mass 0 0 0 0 0 0 0 0.12 Complexviscosity η 1 of respective first resin layers A, B Pa · s 7750 77507750 7750 7750 7750 7750 7750 Complex viscosity η 2 of second resinlayer Pa · s 9450 9400 9700 12050 9400 11800 8300 9450 Complex viscosityratio (η 2/η 1) 1.22 1.21 1.25 1.55 1.21 1.52 1.07 1.22 Evaluation Shapeof interlayer film (only the shape corresponds thereto in the FIG. 1FIG. 1 FIG. 1 FIG. 1 FIG. 1 FIG. 1 FIG. 1 FIG. 1 comparative example)Dark color part 11 Minimum value of parallel light transmittance % 1.11.4 0.8 0.0 20.0 1.1 1.0 1.0 Minimum value of total light transmittance% 61.0 63.0 56.0 8.0 81.0 62.0 60.0 56.0 Length of dark color part (L1)mm 610 600 620 680 400 600 610 600 Maximum value of thickness of firstresin layers mm 0.73 0.74 0.73 0.63 0.55 0.76 0.68 0.76 (T1 + T2)Minimum value of thickness of first resin layers mm 0.47 0.47 0.47 0.470.47 0.65 0.15 0.52 (T1 + T2) Maximum value of thickness of second resinlayer mm 0.29 0.29 0.29 0.28 0.28 0.11 0.60 0.29 (T3) Minimum value ofthickness of second resin layer mm 0.05 0.05 0.05 0.02 0.23 0.02 0.100.043 (T3) Gradation part 12 Length of gradation part (L2) mm 90 90 9015 300 92 88 90 Maximum value of thickness of first resin layers mm 0.780.79 0.79 0.77 0.8 0.79 0.79 0.79 (T1 + T2) Minimum value of thicknessof first resin layers mm 0.73 0.74 0.74 0.63 0.55 0.76 0.68 0.76 (T1 +T2) Evaluation of color irregularity of gradation: ∘∘ ∘∘ ∘∘ ∘∘ ∘∘ ∘∘ ∘∘∘∘ visual observation Evaluation of color irregularity of gradation: ∘ ∘∘ ∘ ∘ ∘ ∘ ∘ transmittance measurement Transparent part 13 Maximum valueof parallel light transmittance % 78.5 78.5 78.5 78.5 78.5 78.5 78.5 61Maximum value of total light transmittance % 88.5 88.5 88.5 88.5 88.588.5 88.5 86 Length of transparent part (L3) mm 1900 1900 1900 1900 19001900 1900 1900 Maximum value of thickness of first resin layers mm 0.820.83 0.82 0.83 0.82 0.82 0.82 0.83 (T1 + T2) Minimum value of thicknessof first resin layers mm 0.74 0.75 0.75 0.76 0.75 0.75 0.75 0.79 (T1 +T2) Maximum value of thickness of second resin layer mm — — — — — — —0.014 (T3) Minimum value of thickness of second resin layer mm — — — — —— — 0.00 (T3) Evaluation of parallel light transmittance of laminatedglass ∘ ∘ ∘ ∘ ∘ ∘ ∘ ∘

TABLE 2 Ex. Ex. Ex. Ex. Comp. Comp. Comp. 9 10 11 12 Ex. 1 Ex. 2 Ex. 3Ingredients First resin layer A Thermoplastic resin Parts by mass 100100 100 100 100 100 100 to be blended (first surface layer) PlasticizerParts by mass 39 35 42 35 39 39 39 Calcium carbonate % by mass 0 0 0 0 00 0 Second resin layer Thermoplastic resin Parts by mass 100 100 100 100100 100 100 (intermediate layer) Plasticizer Parts by mass 30 48 30 4040 40 40 Calcium carbonate % by mass 16.5 2.8 5.9 5.9 0.9 16.7 5.9 Areadensity g/m² 19.2 19.2 19.2 19.2 2.9 18.7 19.2 First resin layer BThermoplastic resin Parts by mass 100 100 100 100 100 100 100 (secondsurface layer) Plasticizer Parts by mass 39 35 42 35 39 39 39 Calciumcarbonate % by mass 0 0 0 0 0 0 0 Complex viscosity η 1 of respectivefirst resin layers A, B Pa · s 7750 9172 6700 9180 7750 7750 7750Complex viscosity η 2 of second resin layer Pa · s 17014 6200 13600 94507800 11900 9450 Complex viscosity ratio (η 2/η 1) 2.20 0.68 2.03 1.031.01 1.54 1.22 Evaluation Shape of interlayer film (only the shapecorresponds thereto in the FIG. 1 FIG. 1 FIG. 1 FIG. 1 FIG. 1 — —comparative example) Dark color part 11 Minimum value of parallel lighttransmittance % 1.1 1.0 1.1 1.1 32.0 0.9 1.1 Minimum value of totallight transmittance % 62.0 60.0 61.0 61.0 84.5 60.0 61.0 Length of darkcolor part (L1) mm 600 610 610 610 — — — Maximum value of thickness offirst resin layers mm 0.76 0.70 0.73 0.74 0.54 0.80 0.82 (T1 + T2)Minimum value of thickness of first resin layers mm 0.68 0.21 0.50 0.510.47 0.73 0.75 (T1 + T2) Maximum value of thickness of second resinlayer mm 0.11 0.60 0.29 0.29 0.29 0.14 0.29 (T3) Minimum value ofthickness of second resin layer mm 0.017 0.092 0.048 0.048 — 0.06 0.22(T3) Gradation part 12 Length of gradation part (L2) mm 92 88 86 90 — —— Maximum value of thickness of first resin layers mm 0.79 0.79 0.780.78 — — — (T1 + T2) Minimum value of thickness of first resin layers mm0.76 0.70 0.73 0.74 — — — (T1 + T2) Evaluation of color irregularity ofgradation: ∘ ∘ ∘ ∘∘ — — — visual observation Evaluation of colorirregularity of gradation: ∘ ∘ ∘ ∘ — — — transmittance measurementTransparent part 13 Maximum value of parallel light transmittance % 78.578.5 78.5 78.5 78.5 — — Maximum value of total light transmittance %88.5 88.5 88.5 88.5 88.5 — — Length of transparent part (L3) mm 19001900 1900 1900 1900 — — Maximum value of thickness of first resin layersmm 0.82 0.82 0.82 0.82 0.82 — — (T1 + T2) Minimum value of thickness offirst resin layers mm 0.79 0.77 0.77 0.79 0.75 — — (T1 + T2) Maximumvalue of thickness of second resin layer mm 0.006 0.030 0.016 0.016 — —— (T3) Minimum value of thickness of second resin layer mm 0 0 0 0 — — —(T3) Evaluation of parallel light transmittance of laminated glass ∘ ∘ ∘∘ x x x

TABLE 3 Ex. Ex. Ex. Ex. Ex. Ex. Comp. 13 14 15 16 17 18 Ex. 4Ingredients First resin layer A Thermoplastic resin Parts by mass 100100 100 100 100 100 100 to be blended (first surface layer) PlasticizerParts by mass 39 39 39 39 39 39 39 Calcium carbonate % by mass 0 0 0 0 00 0 Second resin layer Thermoplastic resin Parts by mass 100 100 100 100100 100 100 (intermediate layer) Plasticizer Parts by mass 40 40 40 4040 40 30 Calcium carbonate % by mass 5.9 20.0 1.8 16.5 2.8 5.9 16.5 Areadensity g/m² 19.2 59.92 5.4 19.2 19.2 19.2 19.2 First resin layer BThermoplastic resin Parts by mass 100 100 100 100 100 100 100 (secondsurface layer) Plasticizer Parts by mass 39 39 39 39 39 39 39 Calciumcarbonate % by mass 0 0 0 0 0 0 0 Complex viscosity η 1 of respectivefirst resin layers A, B Pa · s 7750 7750 7750 7750 7750 7750 7750Complex viscosity η 2 of second resin layer Pa · s 9450 12050 9400 118008300 9450 17014 Complex viscosity ratio (η 2/η 1) 1.22 1.55 1.21 1.521.07 1.22 2.20 Evaluation Shape of interlayer film (only the shapecorresponds thereto in the FIG. 4 FIG. 4 FIG. 4 FIG. 4 FIG. 4 FIG. 4FIG. 4 comparative example) Dark color part 11Ca Minimum value ofparallel light transmittance % 1.1 0.0 20.0 1.1 1.0 1.1 32 Minimum valueof total light transmittance % 61.0 8.0 81.0 62.0 60.0 61 84.5 Length ofdark color part (L1) mm 610 680 400 600 610 610 — Maximum value ofthickness of first resin layers mm 0.77 0.79 0.61 0.79 0.70 0.77 0.54(T1 + T2) Minimum value of thickness of first resin layers mm 0.52 0.540.54 0.71 0.21 0.52 0.49 (T1 + T2) Maximum value of thickness of secondresin layer mm 0.29 0.28 0.28 0.11 0.60 0.29 0.29 (T3 Minimum value ofthickness of second resin layer mm 0.045 0.015 0.193 0.017 0.092 0.045 —(T3) Gradation part 12Ca Length of gradation part (L2) mm 90 15 300 9288 90 — Maximum value of thickness of first resin layers mm 0.78 0.770.8 0.79 0.79 0.78 — (T1 + T2) Minimum value of thickness of first resinlayers mm 0.77 0.79 0.61 0.79 0.70 0.77 — (T1 + T2) Evaluation of colorirregularity of gradation: ∘∘ ∘∘ ∘∘ ∘∘ ∘∘ ∘∘ — visual observationEvaluation of color irregularity of gradation: ∘ ∘ ∘ ∘ ∘ ∘ —transmittance measurement Transparent part 13C Maximum value of parallellight transmittance % 78.5 78.5 78.5 78.5 78.5 78.5 78.5 Maximum valueof total light transmittance % 88.5 88.5 88.5 88.5 88.5 88.5 88.5 Lengthof transparent part (L3) mm 1400 1400 1400 1400 1400 1700 1900 Maximumvalue of thickness of first resin layers mm 0.82 0.83 0.82 0.82 0.820.82 0.82 (TI + T2) Minimum value of thickness of first resin layers mm0.79 0.76 0.75 0.79 0.78 0.79 0.79 (T1 + T2) Maximum value of thicknessof second resin layer mm 0.015 0.050 0.063 0.006 0.030 0.015 0.01 (T3)Minimum value of thickness of second resin layer mm 0.00 0.00 0.00 0.000.00 0 0.00 (T3) Gradation part 12Cb Length of gradation part (L2) mm 9015 300 92 88 90 — Maximum value of thickness of first resin layers mm0.78 0.77 0.8 0.79 0.79 0.78 — (T1 + T2) Minimum value of thickness offirst resin layers mm 0.77 0.79 0.61 0.79 0.70 0.77 — (T1 + T2)Evaluation of color irregularity of gradation: ∘∘ ∘∘ ∘∘ ∘∘ ∘∘ ∘∘ —visual observation Evaluation of color irregularity of gradation: ∘ ∘ ∘∘ ∘ ∘ — transmittance measurement Dark color part 11Cb Minimum value ofparallel light transmittance % 1.1 0.0 20.0 1.1 1.0 1.1 32 Minimum valueof total light transmittance % 61.0 8.0 81.0 62.0 60.0 61 84.5 Length ofdark color part (L1) mm 610 680 400 600 610 300 — Maximum value ofthickness of first resin layers mm 0.77 0.79 0.61 0.79 0.70 0.77 0.54(T1 + T2) Minimum value of thickness of first resin layers mm 0.52 0.540.54 0.71 0.21 0.52 0.49 (T1 + T2) Maximum value of thickness of secondresin layer mm 0.29 0.28 0.28 0.11 0.60 0.29 0.29 (T3) Minimum value ofthickness of second resin layer mm 0.045 0.015 0.193 0.017 0.092 0.045 —(T3) Evaluation of parallel light transmittance of laminated glass ∘ ∘ ∘∘ ∘ ∘ x

TABLE 4 Ex. Ex. Ex. Ex. Ex. Ex. Ex. Comp. 19 20 21 22 23 24 25 Ex. 5Ingredients First resin layer A Thermoplastic resin Parts by mass 100100 100 100 100 100 100 100 to be blended (first surface layer)Plasticizer Parts by mass 39 39 39 39 39 39 39 39 Calcium carbonateParts by mass 0 0 0 0 0 0 0 0 Second resin layer Thermoplastic resinParts by mass 100 100 100 100 100 100 100 100 (intermediate layer)Plasticizer Parts by mass 40 40 40 40 40 40 30 40 Calcium carbonate % bymass 5.9 16.5 2.8 5.9 5.9 5.9 16.5 0.9 Area density g/m² 19.2 19.2 19.219.2 19.2 19.2 19.2 2.9 First resin layer B Thermoplastic resin Parts bymass 100 100 100 100 100 100 100 100 (second surface layer) PlasticizerParts by mass 39 39 39 39 39 39 39 39 Calcium carbonate Parts by mass 00 0 0 0 0 0 0 Complex viscosity η 1 of respective first resin layers A,B Pa · s 8300 7750 7750 8300 8300 8300 7750 7750 Complex viscosity η 2of second resin layer Pa · s 10000 11800 8300 10000 10000 10000 170147800 Complex viscosity ratio (η 2/ η 1) 1.20 1.52 1.07 1.20 1.20 1.202.20 1.01 Evaluation Shape of interlayer film (only the shapecorresponds thereto in the FIG. 5 FIG. 5 FIG. 5 FIG. 5 FIG. 5 FIG. 5FIG. 5 FIG. 5 comparative example) Transparent part 13Da Maximum valueof parallel light transmittance % 78.5 78.5 78.5 78.5 78.5 78.5 78.578.5 Maximum value of total light transmittance % 88.5 88.5 88.5 88.588.5 88.5 88.5 88.5 Length of transparent part (L3) mm 900 900 900 500500 600 900 1900 Maximum value of thickness of first resin layers mm0.82 0.82 0.82 0.82 0.82 0.82 0.82 0.82 (T1 + T2) Minimum value ofthickness of first resin layers mm 0.79 0.79 0.78 0.79 0.79 0.79 0.790.75 (T1 + T2) Maximum value of thickness of second resin layer mm 0.0150.006 0.030 0.015 0.015 0.015 0.006 — (T3) Minimum value of thickness ofsecond resin layer mm 0.00 0.00 0.00 0.00 0.00 0.00 0 — (T3) Gradationpart 12Da Length of gradation part (L2) mm 90 92 88 90 40 90 92 —Maximum value of thickness of first resin layers mm 0.78 0.79 0.79 0.780.78 0.78 0.79 — (T1 + T2) Minimum value of thickness of first resinlayers mm 0.77 0.79 0.70 0.77 0.77 0.77 0.76 — (T1 + T2) Evaluation ofcolor irregularity of gradation: ∘∘ ∘∘ ∘∘ ∘∘ ∘∘ ∘∘ ∘ — visualobservation Evaluation of color irregularity of gradation: ∘ ∘ ∘ ∘ ∘ ∘ ∘— transmittance measurement Dark color part 11D Minimum value ofparallel light transmittance % 1.1 1.1 1.0 1.1 1.1 1.1 1.1 32.0 Minimumvalue of total light transmittance % 61.0 62.0 60.0 61.0 61.0 61.0 62.084.5 Length of dark color part (L1) mm 1000 1000 1000 1800 1800 610 1000— Maximum value of thickness of first resin layers mm 0.77 0.79 0.700.77 0.77 0.77 0.76 0.54 (T1 + T2) Minimum value of thickness of firstresin layers mm 0.52 0.71 0.21 0.52 0.52 0.52 0.68 0.47 (T1 + T2)Maximum value of thickness of second resin layer mm 0.29 0.11 0.60 0.290.29 0.29 0.11 0.29 (T3) Minimum value of thickness of second resinlayer mm 0.045 0.017 0.092 0.045 0.045 0.045 0.017 — (T3) Gradation part12Db Length of gradation part (L2) mm 90 92 88 90 130 90 92 — Maximumvalue of thickness of first resin layers mm 0.78 0.79 0.79 0.78 0.780.78 0.79 — (T1 + T2) Minimum value of thickness of first resin layersmm 0.77 0.79 0.70 0.77 0.77 0.77 0.76 — (T1 + T2) Evaluation of colorirreqularity of qradation: ∘∘ ∘∘ ∘∘ ∘∘ ∘∘ ∘∘ ∘ — visual observationEvaluation of color irregularity of gradation: ∘ ∘ ∘ ∘ ∘ ∘ ∘ —transmittance measurement Transparent part 13Db Maximum value ofparallel light transmittance % 78.5 78.5 78.5 78.5 78.5 78.5 78.5 78.5Maximum value of total light transmittance % 88.5 88.5 88.5 88.5 88.588.5 88.5 88.5 Length of transparent part (L3) mm 900 900 900 500 5001400 900 1900 Maximum value of thickness of first resin layers mm 0.820.82 0.82 0.82 0.82 0.82 0.82 0.82 (T1 + T2) Minimum value of thicknessof first resin layers mm 0.79 0.79 0.78 0.79 0.79 0.79 0.79 0.75 (T1 +T2) Maximum value of thickness of second resin layer mm 0.015 0.0060.030 0.015 0.015 0.015 0.006 — (T3) Minimum value of thickness ofsecond resin layer mm 0.00 0.00 0.00 0.00 0.00 0.00 ∘ — (T3) Evaluationof parallel light transmittance of laminated glass ∘ ∘ ∘ ∘ ∘ ∘ ∘ x

TABLE 5 Ex. 26 Ingredients to be blended Second resin layer AThermoplastic resin Parts by mass 100 (first surface layer) PlasticizerParts by mass 40 Calcium carbonate % by mass 0.45 First resin layerThermoplastic resin Parts by mass 100 (intermediate layer) PlasticizerParts by mass 39 Calcium carbonate % by mass 0 Second resin layer BThermoplastic resin Parts by mass 100 (second surface layer) PlasticizerParts by mass 40 Calcium carbonate % by mass 0.45 Area density of thethinnest portion of respective first resin layers A, B Area density g/m²0.8 Area density of the thickest portion of respective first resinlayers A, B Area density g/m² 3.8 Complex viscosity η 1 of respectivefirst resin layers A, B Pa · s 7800 Complex viscosity η 2 of secondresin layer Pa · s 7420 Complex viscosity ratio (η 2/η 1) 0.95Evaluation Shape of interlayer film FIG. 7 Dark color part Minimum valueof parallel light transmittance % 25.0 11X Minimum value of total lighttransmittance % 83.7 Length of dark color part (L1) mm 1900 Maximumvalue of thickness of second resin layers (T4 + T5) mm 0.79 Minimumvalue of thickness of second resin layers (T4 + T5) mm 0.66 Maximumvalue of thickness of first resin layer (T6) mm 0.13 Minimum value ofthickness of first resin layer (T6) mm 0.00 Gradation part Length ofgradation part (L2) mm 200 12X Maximum value of thickness of secondresin layers (T4 + T5) mm 0.66 Minimum value of thickness of secondresin layers (T4 + T5) mm 0.217 Evaluation of color irregularity ofgradation: visual observation ∘∘ Evaluation of color irregularity ofgradation: transmittance measurement ∘ Maximum value of thickness offirst resin layer (T6) mm 0.573 Minimum value of thickness of firstresin layer (T6) mm 0.130 Transparent part Maximum value of parallellight transmittance % 65 13X Maximum value of total light transmittance% 87.5 Length of transparent part (L3) mm 500 Maximum value of thicknessof second resin layers (T4 + T5) mm 0.217 Minimum value of thickness ofsecond resin layers (T4 + T5) mm 0.170 Maximum value of thickness offirst resin layer (T6) mm 0.620 Minimum value of thickness of firstresin layer (T6) mm 0.573 Evaluation of parallel light transmittance oflaminated glass ∘

EXPLANATION OF SYMBOLS

1, 1A, 1B, 1C, 1D, 1E, 1X, 1Y: Interlayer film

11, 11A, 11B, 11Ca, 11Cb, 11D, 11E, 11X, 11Y: Dark color part

12, 12A, 12B, 12Ca, 12Cb, 12Da, 12Db, 12E, 12X, 12Y: Gradation part

13, 13A, 13B, 13C, 13Da, 13Db, 13E, 13X, 13Y: Transparent part

16, 16A, 16B, 16C, 16D, 16X, 16Y: First resin layer

17, 17A, 17B, 17C, 17D, 17X, 17Y: Second resin layer

18: Third resin layer

21: Laminated glass

22: First laminated glass member

23: Second laminated glass member

51, 51X: Interlayer film

61, 61X: Dark color part

62, 62X: Gradation part

63, 63X: Transparent part

66, 66X: First resin layer

67, 67X: Second resin layer

The invention claimed is:
 1. An interlayer film for laminated glass,being provided with a dark color part, a gradation part and atransparent part, the dark color part, the gradation part and thetransparent part being arranged side by side in a direction orthogonalto a thickness direction of the interlayer film in this order, allowinglaminated glass to have a parallel light transmittance in a portion ofthe dark color part less than or equal to 30% at the time of preparingthe laminated glass with two sheets of clear glass in accordance withJIS R3202 (1996), allowing the parallel light transmittance in a portionof the gradation part of the laminated glass to be continuouslyincreased from the dark color part side to the transparent part side,and allowing the laminated glass to have a parallel light transmittancein a portion of the transparent part greater than or equal to 60%,comprising the following first configuration or comprising the followingsecond configuration: The first configuration: Each of the dark colorpart, the gradation part and the transparent part has a first resinlayer containing a thermoplastic resin and a plasticizer, each of thedark color part and the gradation part further has a second resin layerbeing embedded in the first resin layer so as to allow the first resinlayer to be situated on surfaces at both sides in the thicknessdirection and containing a thermoplastic resin, a plasticizer andinorganic particles, and the thickness of the second resin layer in thegradation part is continuously decreased from the dark color part sideto the transparent part side so as to allow the parallel lighttransmittance in a portion of the gradation part of the laminated glassto be continuously increased from the dark color part side to thetransparent part side; The second configuration: Each of the dark colorpart, the gradation part and the transparent part has a second resinlayer containing a thermoplastic resin, a plasticizer and inorganicparticles, each of the gradation part and the transparent part furtherhas a first resin layer being embedded in the second resin layer so asto allow the second resin layer to be situated on surfaces at both sidesin the thickness direction and containing a thermoplastic resin and aplasticizer, and the total thickness of the second resin layers in thegradation part is continuously decreased from the dark color part sideto the transparent part side so as to allow the parallel lighttransmittance in a portion of the gradation part of the laminated glassto be continuously increased from the dark color part side to thetransparent part side.
 2. The interlayer film for laminated glassaccording to claim 1, wherein the interlayer film comprises the firstconfiguration.
 3. The interlayer film for laminated glass according toclaim 1, wherein the interlayer film comprises the second configuration.4. The interlayer film for laminated glass according to claim 1, whereina complex viscosity at 200° C. of the second resin layer is greater thanor equal to 0.7 times and less than or equal to 2 times a complexviscosity at 200° C. of the first resin layer.
 5. The interlayer filmfor laminated glass according to claim 1, wherein a minimum value of theparallel light transmittance in a portion of the dark color part of thelaminated glass is less than or equal to 10%.
 6. The interlayer film forlaminated glass according to claim 1, wherein a minimum value of thetotal light transmittance in a portion of the dark color part of thelaminated glass is greater than or equal to 50%.
 7. The interlayer filmfor laminated glass according to claim 1, wherein a length of the darkcolor part is greater than or equal to 200 mm.
 8. The interlayer filmfor laminated glass according to claim 1, wherein a content of theinorganic particles is greater than or equal to 2% by mass in 100% bymass of the second resin layer.
 9. A laminated glass, comprising a firstlaminated glass member, a second laminated glass member and theinterlayer film for laminated glass according to claim 1, wherein theinterlayer film for laminated glass is arranged between the firstlaminated glass member and the second laminated glass member.
 10. Thelaminated glass according to claim 9, wherein a complex viscosity at200° C. of the second resin layer is greater than or equal to 0.7 timesand less than or equal to 2 times a complex viscosity at 200° C. of thefirst resin layer.